@@PineHollowAutoDiagnostics Wait... you charged the battery, diagnosed the problem, while shooting a video, AND got the knock sensor ordered and delivered (!!) all within one hour? OK, I'm much more impressed with that than the bit about replacing the component that the trouble code said to replace 🙂. (OK, I do get that the moral of this video is to rigorously question one's assumption that Problem B couldn't possibly have anything to do with Problem A.)
Over many years I’ve realised that Google is your friend - as you said it’s vital to search on the correct terms, typically it’s going to have occurred before. In my 20’s I worked for HP as an engineer, my Parts controller (storeman) could diagnose faults on products just from the parts usage he saw on his parts system. If you asked for something obscure he would as ‘what makes you the only engineer in the world to request that part’!
I've found that more manufacturers are tying in simple faults that normally wouldn't affect drivability to more critical functions just to get the owner to get the simpler things fixed. My Subaru Forester for example had the P0420 catalytic converter code. This made it lock out the cruise control and traction control. Bells and whistles. The more there are, the more to break.
About 25 years ago when training as a Bosch techie, heard a story about a Nissan that came in with a problem. This was the early 90s so fuel injection and engine management were still new. Car apparently had an issue when towing a trailer. At certain speeds the car started losing power as if the throttle was being held back. With no trailer it was 100%. And with trailer, it was speed dependant, and not gear dependant (I.e. not engine rev related). To make matters more interesting it turned out to be one specific trailer, as other trailers towed fine. After a little investigation it was discovered that the trailer hitch was for a 2inch ball, but the tow ball on the nissan was 50mm. At certain speeds the .8mm difference was enough for the trailer to oscillate at high enough frequencies on the ball to send a false frequency through the chassis and mounts to the knock sensor.....
It shows transmission shops don't always know enough to care or research the issues. Isn't google cool sometimes. It was also sweet that someone was willing to share their problem and eventual solution. The customer must have been ecstatic. Great job Ivan and for not limiting your options.....Pete
@@knocksensor3203 - that makes sense. This simple repair was only 0.5 hours according to the Ivan's online book. Why should a shop fix a customer's car and only make 0.5 hours when they make easy money fixing transmissions? (thank gawd there are shops like Ivan's that have integrity)
This in so many ways is absolutely ridiculous. Fair play Ivan for fixing it and getting to the bottom of this, but how in the name of God can a shop keep this car for 8 months and still not fix what is frankly under their nose with a bit of research that is available to everyone. Well done Ivan. Easy one for those of us in the know 😀
I've learned that lesson the hard way working in maintenance in a factory. Don't leave any obvious faults behind you, even if they don't seem related. They will sink you every time.
@@russellhltn1396 I would say a connection with the software. The ecm sensed a problem and disabled the transmission. Don't know why it didn't set set a transmission code. I guess you should just figure that out from the knock sensor fault.
@@randallgoldapp9510 It didn't set a transmission code because there was nothing wrong with it. What's missing is a note that should be in the service manual that indicates this is a limp mode caused by engine issues. I'm not sure how much freedom the makers have for creating custom error codes.
@@russellhltn1396 The main point is don't ignore an obvious fault just because it doesn't seem related. This is a common trouble shooting mistake I see a lot. It really isn't important why they are related, it is that they are related that's important. don't worry about why, clear the fault and move on.
...geez...who would'a thunk it....a knock sensor causing the transmission to go into limp mode....Ivan, your diagnostic skills continue to amaze me....this was a very enjoyable and informative video....thanks for posting... 🙂
Wow the reverb on that exhaust would drive me nuts, Super diagnosis Ivan, fixed for a $70 part, plus Battery and your time of course. I have a feeling you just earned another customer!. Stay safe thank you for the time you put into the videos. The more content the more answers solved and the world gains all this knowledge.
when it showed the knock sensor code I thought the engine is in limp mode for sure the 3rd gear on the dash thru the customer for a loop for sure and probably made him go the wrong route with the trans shop. thanks for all the good videos
The sad part is that the guy at autozone could have fixed this car at the parking lot, just to throwing parts and no really knowing how to properly do a diagnostic. Great job Ivan 👍
I have seen this personally. In one recent case, a local transmission shop put two dealer supplied transmissions into a Hyundai, and they still couldn't figure out why the transmission wasn't operating properly. They called in an outside trouble shooter, who within an hour, determined that the harness connection to the transmission had been compromised and needed to be replaced. The vehicle never needed a transmission in the first place.
Another great diagnosis! By the way, the colourful material on the top of the dashboard at 4.59 was probably what the owner was thinking when the car went into limp-mode....just a thought....!
I'm Dan, Martha's my wife. Great diagnosis Ivan. Funny how complicated vehicles are today and how something you'd think would nothing to do with the problem would be the cause of the problem. Knock sensor/trans. problem, who'd have thunk it.
That is a killer outcome! Sometimes, it's OK to trust what's in your face. While it is true you never know when for sure, but, your instincts are sharp and your nose for little hints and a fine tuned GUT FEELING, serve you extremely well! Stick a fork in that car, it's DONE! Congrats, Ivan! Keep on making it look sickeningly easy! 👏👏👏👍👍👌
Your comment about doing a search reveals something - too many people think that you need to be super technical when you are looking for either a part or to help diagnose a problem. Years ago you had to be pretty specific on how you phrased questions, but in our more modern times, you can type it in the same as you'd ask a friend, and often times you'll get some amazing results. We just encountered almost this exact issue with the AC in my RV as it failed, and trying to find a simple expansion valve on the RV sites was a nightmare. Typed in a simple search for RV AC expansion valve and discovered that the local Advance Auto had almost the same exact valve as what I had been looking for days for using more technical terms. In a nutshell, type in your search using the KISS principal and see what it does - it might shock you!!
This is like an extreme version of what happens to Toyotas (and maybe other manufacturers): when the knock sensor code prevents engagement for some gears. I've seen a Nissan (1st gen Xterra V6) have consistent misfires (flashing MIL) under medium to high loads while in motion (i.e. Drive) simply because of a bad knock sensor. The misfire didn't happen when revving the engine in Park or Neutral. P.S: Bless Mazda for that knock sensor location on this V6. Most other OEMs hide them in the valley.
@@marlu6373 The knock sensor in the Xterra I referred to failed due to corrosion from the cast Iron engine block and a slow leakage from the corroded metal coolant pipe alongside it right at the bottom of the V6 engine valley.
Great thing to see how these things work That actually happened with my 05 Toyota Sienna, it was not releasing OD just because of a faulty KS. Thanks Ivan for helping people with honesty.
Sometimes, to diagnose a malfunction, just say OK Google 😎 Thank you Ivan! This car will be like new! If you do not take into account the sagging ceiling 😁
Mazda 6 Wagon....unicorn. Google search to the rescue of a limp mode Mazda. ~10 ago not knowing better about going OEM, installed a BWD/Intermotor (div SMP) camshaft position TDC sensor form Advance on Civic, Still working like a champ. I think they make decent parts (sensors at least) for Asian vehicles. This one time, scan code alone was spot on solving trans limp mode issue. Who'd a thunk it. I'm sure owner happy to have his unicorn back in action. Nice job Ivan.....again. 👍
Nice job! This video reminds me of one ScannerDanner did of an Audi that had no power. It had a code for a faulty electronically controlled engine mount that everyone ignored thinking that couldn't possibly be the problem... But it was setting the engine into limp mode without any indication it was being derated. Btw, the slamming into gear is normal. When transmissions go into limp mode they default to maximum line pressure. This causes VERY aggressive gear shifts. These transmissions are some of the most uncomfortable for that. Good job at keeping an open mind!
Thank you Chrysler for making it easy to read codes on 96 and and newer vehicles. Cycle ignition key 3 times on and off and on the 3rd time, leaving it in the ON position, the dtc codes pop up on the odometer. That's how i keep my my 20+ year old Durango and Dakota running and my previous 4 Grand Cherokees.
Watching you cover so many topics, I have learned to look at everything going on with a car. AND visual inspection! My daughter's car had a blower motor issue and all my research led to a wiring problem near the fuse box. But, performing a visual inspection on the wiring in the circuit, the resistor had gotten so hot, two of the wires had melted together shorting the circuit. A new pigtail connector and it's fixed! The resistor was fried, that was the original cause of the problem.
I HATE transmission shops. NEVER had a good experience with them. I learned though- when my 76 GranTorino's tranny quit- I went to the junk yard and got one for $100 (back in 79) - took me and my buddy a week to do the swap- worked perfect. Learned a ton. Had to rent a transmission jack- but that thing was amazing. Anyway- Ivan, you are amazing. I hope that customer didn't pay those other guys anything. A whole year down because nobody wanted to THINK... other than Ivan of course. What baffles me, why NOT replace the knock sensor?? The code came up on the scanner- the part is south of $100 and it's pretty much in front of your face after you remove the BAD battery. Even if it's a "no way it's the knock sensor" thing- you've eliminated a 'possible'. Again Ivan- just awesome. I'd DEFINITELY travel 3 hours to have Ivan look at a problem.
Lesson of the day is ; Mazda engeneers build in a safety feature if knock sensor fails or noticed an abnormalty, the drive train should go into limp mode. Anyway excellent find Ivan.
8:12 "I guess anything is possible" is the ultimate wisdom in this field and every other field. I remember I was diagnosing a car that had shift problems, maybe even had the same symptoms, and the code that was set in TCM was a) unheard of b) had no information about it on the internet c) there were codes stored in the PCM that has no relation whatsoever with the transmission or how should it shift. After almost 3 days of trying to figure out the problem it turns out that one of the codes in the PCM that was caused by a MAP sensor that lost a ground wire causing the transmission to go in some sort of limp mode and make hard to shift gears, exactly like this car with different sensor and error causing the problem. The car was a Renault, a french car and I will NEVER forget this car ever.
I seriously wish I could shadow you for a few weeks and watch you work. Its extremely impressive the way your brain works through some of these issues. Hell, i'd glady work for free the entire time. I legit have 26 years experience as a paid professional automotive tech but i couldn't hold a candle to what you do and am pretty envious of the level you're at in this field. Definitely one of my idols. No bs. And I don't have too many. Staten Island Keith is one. Mr Danner is another. Mr and Mrs O, Perkins, Brin Klein, Cody, Super Mario. Cuba, Mech Mindset. Steckler, Pete Meier, Jerry Truglia, Mike Becker, Bernie Thompson, and plenty more but its late and my brains slowing down so I apologize for leaving a few out. What I'd give to be a fly on the wall.
its not just Ivans gift of mechanical and electrical skills., its his control of emotions.. he doesnt seem to get angry or aggravated by most problems. he is able to clear the clutter from previous attempts. and focus. most techs experience alot of pressure and fear because you are against the clock. he is very even keel emotionally. has a positive attitude and is very determined to find the root problem.
Yes! All that was said is very true! He's worked on old motorcycles bringing them back to life. He's spent time in Russia where thinking outside the box was definitely required. Not sure how long. Keith (New level auto diagnostics) took him under his wing for a week or so. I believe he's an EE that was working on his masters and got tired of the 9-5 drag and went out on his own. Ivan, did I miss anything or something needing correcting?
I am not sure shadowing him would help. He is a trained engineer who knows how to be analytical. Using all available tools including scopes, pressure transducers and the best scanners. He has built up large amounts of experience by taking the harder diagnostic specialty route and no employees rather than the common and repetitive shop track. His wife is a professional which no doubt allowed him time to build his strengths before he became as proficient as he is today. And the small things. The use of a notebook to record steps and measurements. Knowing how to use search terms effectively by guessing terms likely to be in the answer. Occasionally phone a friend. Finally he was smart enough to visit youtubers like Eric O and listen when Eric encouraged him to do youtube. Now Ivan's youtube income may surpass his customer income.
@@dans_Learning_Curve its also genetics.. his father was a nuclear scientist.. the apple usually doesnt fall far from the tree. Teaching people when they are young how to do deductive reasoning, utilize thier resources, and look at challenges as an interesting project rather then grueling work carries thru the adult life of the person. Ivan always says "this should be a fun case study". he has a different attitude. than your average Joe and is not so prideful that he is ashamed to ask for help at times.. he is smart enough to know that he doesnt know everything.
One of our 2003 S-10's would intermittently want to start out in 3rd gear. I noticed the alternator making noise and the scope showed problems with the rectifier bridge. Replaced the alternator and the transmission never acted up again! Great video!
9:38 extremly lucky that the person asking that question actually followed up with how they fixed it instead of generic "nvm i fixed it" or "idk what happened but it fixed itself"
It is a good idea to check the alternator first. My 2005 Mazda 6 went into limp mode a few years ago and it turned out that the alternator was bad. I had the alternator replaced with one from O'Reilly's and it fixed the issue for about a month--until the car went into limp mode again. The alternator ended up still being the culprit. The problem is that at places like O'Reilly's or AutoZone sometimes the remanufactured alternators are not rebuilt properly. I learned that it is a good idea to have alternators and car batteries always bench tested at the store before buying them to spare yourself from future headaches. Hopefully this tip will help someone.
Ivan, another job completed. As I'm concerned about your safety, did I see you do that "test drive" without your seat belt on? We need you Ivan. :-) A loyal follower, mike
I’m an Aussie and grew up with belts, they are just built into our brains from kids. It really does hurt my brain to see so many Americans on so many platforms simply not putting them on.
Wow, well, all the trouble codes can be interrelated to everything. Damn knock sensor knocking out the transmission! Damn good fix Ivan! Great job fixing an hour of diagnosis! Wow unreal. I can't believe it lol
Yup! I worked heavy duty and if you needed to remove the fuel.tank or the crossover hose, the tank would be full. If you had to dyno it the tank would be MT.
As the solution vs mechanic diagnostic history shows, people have a reason to bring a car in with no gas. It's a known and shitty practice that "cool" cars are "test" driven fast beyond normal acceptable parameters. A mechanic should simply ful the tank as needed and charge the customer per gallon used via trip odometer. Trust should not be required for any trades repairs. Logic, detailed, explanations that are observable and/or replicable should be standard practice before applying repairs. Issues with process addressed as needed throughout that will add to the bill. I understand there are exceptions to any rule, however... Good mechanics or tradesmen are now the exception vs standard.
Yup! K.I.S.S rule first… just a little farther info. Knock sensor was retarding the timing to prevent engine damage. Also putting trans in limp mode (which we know lol) 3 gear is most likely a 1:1 ratio. So putting as little strain on the trans too. That’s also why reverse worked. Direct drive (input and output shafts locked together) inside the transmission. Just turning in opposite direction. Good video!
Super stuff, really enjoyed that. All of these videos just reinforce my view that manufacturers have made cars so complex they are almost unfixable making them technologically obsolete so we need to buy another one when anything goes wrong. Heard hundreds of tales of cars and bikes taken in to dealerships charging top rates and unable to fix them.
Great pickup Ivan! Mazda should really issue a TSB or some sort of instruction to alert mechanics (including their own) of this issue that can cause the transmission to go into Limp/Safe mode. It is way out of left field that a knock sensor would cause this transmission issue!.
Ivan. Logically. If the engine indeed had a slight knock. Would it make sense to try to save the engine and transmission. That's why the transmission was in limp mode? Because I've had customers had a noticable knock and they were revving the engine even more 😂 Saying o...it's been like that I'm just driving it till it gets worse. Duh
Really this shows that DATA is important... if manufacturers listed the CONDITIONS that can TRIGGER a limp mode... then you can just look it up but no they all have to be secretive about their damn software then years later they just act like they never made the car and no-one can see the data it's all so stupid
When you said it had a knock sensor code I was betting that was it as you have said in the past on newer vehicles anything can cause all sorts of problems to show up on the CAN BUS HIGH/LOW.I bet the customer was pissed .Cheers another good video.
Definitely some questionable programming in that TCM software to go into limp mode for a fault like that. I could maybe see if they were trying to avoid the engine pinging or something, but I'd think locking it in 3rd from a stop would only make that worse.. Reminds me of the GM vehicles which would keep the cooling fan running all the time with literally any DTC set.
@@keltecshooter And there being no code in the TCM saying it's in limp mode because of a dependency on a fault code in the PCM. Meanwhile the PCM wasn't in limp mode at all...
isnt the simplest fix often the correct one. Just cant fix what you don't understand how it works. Great work! That is how my apprentices are taught to think.
The PCM firmware was programmed to put the TCM into limp mode with a knock sensor fault. Likely the best approach is to have not codes ever. If one pops up then whatever change in the vehicle behavior occurs is related to the code.
@@SirDeanosity Yes. Thanks for the information. Always glad to learn. There are some smart people out there. I am not necessarily one of them so I am still driving my 1989Honda CRX HF that I bought new in Jan. 1989. It has over 377,000 miles on the odometer and has never been in the shop. The simplicity of the car matches my skill level perfectly. I don't have any power windows or seats, no airbags, no traction control, lane assist, power mirrors, automatic transmission, cruise control, infotainment system or anything else. I don't even have a cupholder. It was, and is still, basic transportation that has never broken down on me once and I have kept it that way with just preventative maintenance. Not one drop of oil has even hit the ground. It still blows 40 degrees through the center vent with the air conditioner on which is a godsend here in the deep south. It is a trusted piece of history to me and will never be for sale. I love the PHAD channel for Ivan's great diagnostics and how often he is able to fix something with no parts required and his sincerity and honesty. Have a great day.
had an 06 6s (v6) and it was a love hate, Loved driving the car, comfortable, good torque. Hated the front seal and valve cover (replaced) oil leaks and most of all the garbage aisin 6 speed transmission. in 140K the engine never gave me any real issues, but I did have 3 replacement transmissions under warranty. Trans would flair between shifts with at full operating temps. On the highway, peddle down it would buck between gears felt like the powertrain was going to fall out. Glad Mazda is wholly owned again, love my 17 Mazda 6, no a lick of trouble.
A few years back my W140 S-Class Mercedes would jump out of cruise control on the motorway, ABS light would come on and power reduced..... FIX.... a new brake light switch on the brake peddle. Go figure. So you are right, fix what is broken on modern cars, the faults may all be interlinked. Good troubleshoot👍🏻👍🏻
Toyotas had an issue similar to this. If knock sensor faults were set on the 3.3L v6 engine, the transmission would shift through all gears fine the first time but would not shift into overdrive or 4th gear afterwards. Would need to shut the car off and restart it. Replace the knock sensor and sub harness, shifting would return to normal.
What did we learn? There is a software bug most likely in the transmission controller. The PCM will broadcast the P0328 fault to the other powertrain modules on the bus. Putting the transmission in limp home mode will not address engine detonation. The PCM will address a bad knock sensor by changing the spark advance to limit the chance of detonation. The only strategy that I know of that could cause a system wide reaction to a bad knock sensor is if the PCM strategy used active knock. Which is a way to enter a knock condition given a set of engine drive cycle parameters to test the system and other things like fuel octane estimate. However, when a knock sensor is bad or the connector disconnected, active knock should be disabled. Perhaps there is a software update for the TCM? For a transmission in limp home mode for an extended time, I would do a fluid and filter change. Perhaps not a complete transmission flush unless the fluid looks and smells bad. So, at minimum, just the fluid in the pan and the filter. But, be warned dropping the pan may not be easy and in doing so you may require a new pan gasket. However, by inspecting the pan and any debris you can get a feel for if the transmission has been abused by limp home mode. Perhaps the transmission shop already changed the fluid and the filter? If you do a test drive after limp home mode and you feel a TCC shudder or an overdrive shift shudder, then replace the fluid and filter. If you are doing a complete flush you could try using a synthetic blend transmission fluid from Mobil 1 which I have found has a slightly higher viscosity than most factory fluid which helps eliminate shudder if you do a complete flush (change).
Ivan, future reference herre with Mazdas like this one that have Ford engines....and yes this is a Ford V6. If you want OEM parts, call the local Ford dealer. I don't know how many times I've had to contact our local Ford dealer to get parts that Mazda says "we don't have that".
BRAVO Like you said fixed what's broke. You also revealed big secret on internet searches. KEYWORDS people. I work in I.T. and shade tree work on cars. (Hey a computer is a computer) Doesn't matter if it is on your desk or in a car they function is the same. Specific keywords like Ivan showed will often give you the answer you are looking for.. Nice job my friend.
Made me smile Ivan.....You said "as good as new" and the head lining was flapping around like a main sail on an ocean going yacht lol.....Great video again matey....Saludos desde Esaña mi amigo....
I faced similar in a 2013 Toyota Venza... Knock sensor codes and transmission goes gaga... However not exactly in limp mode, but give a violent jolt between 2 and 3. Nice job as always
I diagnosed a no comm for tcm, missing certain gear, sticking. Bought the car, Mazda 5 , 2008 van, 147k miles from owner for $750. Ordered a refurbished tcm from California. They were plug and play. DONT mount it on the transmission, rather on the firewall with a couple zip straps. The heat from the transmission causes this issue. The transmission would slam, hit into 3rd as well. Replaced tcm, cleared codes and has worked great since this last year.
Very cool! I would love to see the program logic on how the transmission goes into limp mode because of a knock sensor. They must have had a reason. lol
Watched this before leaving for work this morning. I told Gloria it was the knock sensor as soon as You said it had that code! How did I get so good? (Lucky for once) There is nothing wrong with a quickly once in a while! 👍👍🇺🇸🇺🇸
On Japanese cars, the transmission is always getting a "torque signal" from the PCM/ECM, so it can "prep" for shift's. It's one of their secrets for smooth shifting and reliability I feel. lol The bad knock sensor meant that the PCM couldn't properly calculate the torque signal, as it didn't know the knock condition (which would definitely throw the actual torque off of the signal, if the engine was knocking and the PCM couldn't tell) so it was likely shutting off the torque signal. It wasn't until 2010 or so when the OEM's thought to have the no torque signal condition actually trigger a readable code from the TCM. So as you said at the end of the video, always fix codes in other modules before chasing specific rabbit holes.
Also reminds me of an issue I saw when I was in college. Had a UPS (battery backup) in our lab which would not communicate with any of the computers in our lab via serial port/RS-232. Since I was one of the better students and had all my assignments caught up, the professor put me on the job as classes for the prior two years could not figure it out either. So, I noticed since they had us wipe the lab computers so often, they were just using drivers built into Windows XP. So I just started updating drivers one at a time and trying the communication, starting with anything that *could* influence the serial port. Nothing there. So moved on to every other driver. As soon as I installed the video card driver, it started communicating. On the next lab computer, I installed just the application for the UPS and the video card driver, and it worked on that too. TL;DR: I once had a video card driver influence how a computer communicated to a battery backup via an old serial port (like USB before USB was a thing.)
People are worried about throwing parts at a car if there is a serious issue I can understand that. Not sure what that part cost. I would had that replaced if it were under 100 dollars with labor or if I could had done it myself.. Great Video and Excellent job.. I am waiting for Vehicles to go into limp mode for a low tire
Ivan, I think all that car needed was a nice day. Great to see you enjoying the weather while doing what you do. Makes us all feel good! Thanks for Sharing!
I have not run into this problem before. That's something good to know though. But I have had a Ford Taurus V6 no start because of a bad ECT sensor. That was a bit misleading. I have found that sometimes it's worth looking into those little issues that are seemingly unrelated.
Wow, what a fun little wagon. I’m going junk my M3 Hatchback/station wagon when the transmission fails soon and I’m going to find an M6 Hatchback/station wagon to replace it.
the knock sensor is for what ..... to tell the computer of a problem ...... the computer can only know /respond to what it is told ..... that's my take on it .... me : not a mechanic
@@ivanolsen7966 the knock sensor is to detect engine knock (fuel knock) so it can back off the ignition timing. It's part of a feedback system, not a problem detector. Forcing transmission limp mode is extremely odd behavior for that sensor. Engine limp mode can be expected, but a perfectly running engine and only the trans in limp mode? It's very odd.
I agree with you about the availability of information on the internet being helpful, but I have also seen a couple of negatives. I have been a technician for over 30 years and have trained several techs over the years. I have seen young guys who would rather try to find their answers with a Google search than actually learn how to diagnose a problem.
Same thing on an 03 Taurus. Stuck in 3rd gear. 2 transmission shops said it needed new transmission. 3 egr codes and 3 transmission codes. Found that egr and transmission shared same circuit and wires were melted on egr pipe. New fuse and a quick wiring repair and the car was fixed after 1 year of sitting.
This one didn't surprise me at all---anything that puts the car into limp-home mode can impact other systems. Parts required, but not expensive ones = win
I had a 2002 VW beetle. It was throwing ABS error codes. Car under warranty. The dealership replaced ABS sensors 2 or 3 times. It was 20 miles round trip to the dealer. Driving me nuts. I called VW customer service, gee the multi-pin connector from the engine compartment to get wiring through firewall, had been sprayed inside with insulating foam only meant to keep water out of the inside of the car. Factory error created a short for the ABS system. It is nice to see that we have dedicated techs that can actually diagnose a problem. VW bought the car back from me under the California Lemon Law.
Crazy I have a 2007 mini cooper with a CVT car went in to limp mode due to a tach having and intermittent com problem , I noticed the tach blink before the limp/EP mode , Found one post on a forum contacted the guy to confirm we had the same issue i disconnected the tach and drove car with no issues I spent weeks tracing wires and checking modules Great job
Somehow get onto that original guy/gal and you thank them profusely. One time I searched you tube on how to reset the oil change reminder on my car. I found a 6 year old vid and said thanks heaps in the comments and the vid poster was very happy that he could still be if help that many years later. This tranny vid is from 2011.
I have fixed countless transmissions in limp mode but have never heard of this one before. Must be a secret known only to certain Mazda Techs and engineers. Can't believe there are no factory diagnostics for this or a pairing code set in the TCM. Hopefully Ivan you post this tech tip in Alldata.
Thanks for the video Ivan great job 👍❤️❤️ it. My Subaru outback had a Abs code and O2 bank 1 and Temp sensor. Fixed the Abs code and all good.😅. Take care of yourself and family and be Blessed ❤️❤️❤️.
That is interesting that it didn't set at least a generic po700 or at least something stating it was indeed in limp home mode. Kinda makes me wonder if you could recreate the same issue, by perhaps disconnecting another major sensor like a CTS?
Hello from London. My car kept going into limp mode with similar transmission issues (automatic box stuck in 3rd. and illuminated engine light). I was dreading the cost of a new gearbox but was advised (by telephone) by my dealer to check if the petrol filler cap was tight. I thought it was, but he suggested removing it, blowing hard into the filler, leaving it for 10 minutes and then replacing until I heard two or three clicks. Turned out that the sensors had detected fuel vapour which wasn't being dispersed properly! They had seen several owners of my model with the same issue.
You were so worth that 3 hour drive! Nice job Ivan!
Customer was very pleased... And surprised that the car was repaired within an hour of getting dropped off 😅
@@PineHollowAutoDiagnostics And he was back home in time for dinner too!!!
Wow nice diag Ivan!
@@PineHollowAutoDiagnostics Wait... you charged the battery, diagnosed the problem, while shooting a video, AND got the knock sensor ordered and delivered (!!) all within one hour? OK, I'm much more impressed with that than the bit about replacing the component that the trouble code said to replace 🙂. (OK, I do get that the moral of this video is to rigorously question one's assumption that Problem B couldn't possibly have anything to do with Problem A.)
Over many years I’ve realised that Google is your friend - as you said it’s vital to search on the correct terms, typically it’s going to have occurred before. In my 20’s I worked for HP as an engineer, my Parts controller (storeman) could diagnose faults on products just from the parts usage he saw on his parts system. If you asked for something obscure he would as ‘what makes you the only engineer in the world to request that part’!
I've found that more manufacturers are tying in simple faults that normally wouldn't affect drivability to more critical functions just to get the owner to get the simpler things fixed. My Subaru Forester for example had the P0420 catalytic converter code. This made it lock out the cruise control and traction control. Bells and whistles. The more there are, the more to break.
This is a life lesson for troubleshooting. It's hard to imagine the car was parked for almost a year for an hour's worth of work. GREAT VIDEO!
About 25 years ago when training as a Bosch techie, heard a story about a Nissan that came in with a problem. This was the early 90s so fuel injection and engine management were still new. Car apparently had an issue when towing a trailer. At certain speeds the car started losing power as if the throttle was being held back. With no trailer it was 100%. And with trailer, it was speed dependant, and not gear dependant (I.e. not engine rev related). To make matters more interesting it turned out to be one specific trailer, as other trailers towed fine. After a little investigation it was discovered that the trailer hitch was for a 2inch ball, but the tow ball on the nissan was 50mm. At certain speeds the .8mm difference was enough for the trailer to oscillate at high enough frequencies on the ball to send a false frequency through the chassis and mounts to the knock sensor.....
@@alphaomega5721 that is truly crazy! 😳
It shows transmission shops don't always know enough to care or research the issues. Isn't google cool sometimes. It was also sweet that someone was willing to share their problem and eventual solution. The customer must have been ecstatic. Great job Ivan and for not limiting your options.....Pete
They (shops) just want easy repairs and quick money…
@@knocksensor3203 - that makes sense. This simple repair was only 0.5 hours according to the Ivan's online book. Why should a shop fix a customer's car and only make 0.5 hours when they make easy money fixing transmissions? (thank gawd there are shops like Ivan's that have integrity)
That connector being previously disconnected means somebody was so close but yet so far. Being able to ohm out the sensor made all the difference.
I guess they figured that if they removed it from the circuit, it couldn't cause a problem..... 😉
Guy probably got pulled off of the job before he finished the diagnostic ...
I don't have all data but Google is amazing. That is if Ivan hasn't already solved my problem before. Glad to see think tool back in operation.
This in so many ways is absolutely ridiculous. Fair play Ivan for fixing it and getting to the bottom of this, but how in the name of God can a shop keep this car for 8 months and still not fix what is frankly under their nose with a bit of research that is available to everyone. Well done Ivan. Easy one for those of us in the know 😀
I have said this for MANY YEARS, Fix what you know is broken. As usual, well done!
I've learned that lesson the hard way working in maintenance in a factory. Don't leave any obvious faults behind you, even if they don't seem related. They will sink you every time.
I've done the same. But I'd like to know what made these things related.
@@russellhltn1396 I would say a connection with the software. The ecm sensed a problem and disabled the transmission. Don't know why it didn't set set a transmission code. I guess you should just figure that out from the knock sensor fault.
@@randallgoldapp9510 It didn't set a transmission code because there was nothing wrong with it. What's missing is a note that should be in the service manual that indicates this is a limp mode caused by engine issues. I'm not sure how much freedom the makers have for creating custom error codes.
@@russellhltn1396 The main point is don't ignore an obvious fault just because it doesn't seem related. This is a common trouble shooting mistake I see a lot. It really isn't important why they are related, it is that they are related that's important. don't worry about why, clear the fault and move on.
Does it have hydraulic fluid? Is that Hydraulic Fluid? 😂 "I think so." Always ask the "Stupid Questions"
...geez...who would'a thunk it....a knock sensor causing the transmission to go into limp mode....Ivan, your diagnostic skills
continue to amaze me....this was a very enjoyable and informative video....thanks for posting... 🙂
You too can google.
Wow the reverb on that exhaust would drive me nuts, Super diagnosis Ivan, fixed for a $70 part, plus Battery and your time of course. I have a feeling you just earned another customer!. Stay safe thank you for the time you put into the videos. The more content the more answers solved and the world gains all this knowledge.
when it showed the knock sensor code I thought the engine is in limp mode for sure the 3rd gear on the dash thru the customer for a loop for sure and probably made him go the wrong route with the trans shop. thanks for all the good videos
The sad part is that the guy at autozone could have fixed this car at the parking lot, just to throwing parts and no really knowing how to properly do a diagnostic.
Great job Ivan 👍
Haha, exactly! The magic codes would have fixed it.
The owner is very lucky. A lot of transmission shops would have tried to sell him a full rebuild.
Thank goodness they didn't go that route!
I have seen this personally. In one recent case, a local transmission shop put two dealer supplied transmissions into a Hyundai, and they still couldn't figure out why the transmission wasn't operating properly. They called in an outside trouble shooter, who within an hour, determined that the harness connection to the transmission had been compromised and needed to be replaced. The vehicle never needed a transmission in the first place.
true
Another great diagnosis! By the way, the colourful material on the top of the dashboard at 4.59 was probably what the owner was thinking when the car went into limp-mode....just a thought....!
I'm Dan, Martha's my wife. Great diagnosis Ivan. Funny how complicated vehicles are today and how something you'd think would nothing to do with the problem would be the cause of the problem. Knock sensor/trans. problem, who'd have thunk it.
That is a killer outcome! Sometimes, it's OK to trust what's in your face. While it is true you never know when for sure, but, your instincts are sharp and your nose for little hints and a fine tuned GUT FEELING, serve you extremely well! Stick a fork in that car, it's DONE!
Congrats, Ivan! Keep on making it look sickeningly easy! 👏👏👏👍👍👌
Your comment about doing a search reveals something - too many people think that you need to be super technical when you are looking for either a part or to help diagnose a problem. Years ago you had to be pretty specific on how you phrased questions, but in our more modern times, you can type it in the same as you'd ask a friend, and often times you'll get some amazing results. We just encountered almost this exact issue with the AC in my RV as it failed, and trying to find a simple expansion valve on the RV sites was a nightmare. Typed in a simple search for RV AC expansion valve and discovered that the local Advance Auto had almost the same exact valve as what I had been looking for days for using more technical terms. In a nutshell, type in your search using the KISS principal and see what it does - it might shock you!!
Just be careful when searching for a Big Block Chevy 😂
Man oh man ,you are super, you can fix anything, I wish all shops had people like you,way to go
This is like an extreme version of what happens to Toyotas (and maybe other manufacturers): when the knock sensor code prevents engagement for some gears. I've seen a Nissan (1st gen Xterra V6) have consistent misfires (flashing MIL) under medium to high loads while in motion (i.e. Drive) simply because of a bad knock sensor. The misfire didn't happen when revving the engine in Park or Neutral.
P.S: Bless Mazda for that knock sensor location on this V6. Most other OEMs hide them in the valley.
my 97 nissan quest was chewing knock sensors like there is no tomorrow.i think it was the bad position they chose to mount it.
@@marlu6373 The knock sensor in the Xterra I referred to failed due to corrosion from the cast Iron engine block and a slow leakage from the corroded metal coolant pipe alongside it right at the bottom of the V6 engine valley.
Great job as usual!
@@AnnaWaipa-bq7dd Thanks, but "as usual"? I don't quite understand.
Great thing to see how these things work
That actually happened with my 05 Toyota Sienna, it was not releasing OD just because of a faulty KS.
Thanks Ivan for helping people with honesty.
Sometimes, to diagnose a malfunction, just say OK Google 😎
Thank you Ivan!
This car will be like new!
If you do not take into account the sagging ceiling 😁
I love watching Ivan. I can't wait to get home every night after work to see if he has a new video out.
I like when he drops vids in the morning. Very pleasant way to start the day.
Why is that? Because he does what 90% of the rest of the world doesn't do.
THINK!
Nothing I hate more than 'stupid people' They grate on my nerves! And that is generally how the world is going.
Mazda 6 Wagon....unicorn. Google search to the rescue of a limp mode Mazda. ~10 ago not knowing better about going OEM, installed a BWD/Intermotor (div SMP) camshaft position TDC sensor form Advance on Civic, Still working like a champ. I think they make decent parts (sensors at least) for Asian vehicles. This one time, scan code alone was spot on solving trans limp mode issue. Who'd a thunk it. I'm sure owner happy to have his unicorn back in action. Nice job Ivan.....again. 👍
Nice job! This video reminds me of one ScannerDanner did of an Audi that had no power. It had a code for a faulty electronically controlled engine mount that everyone ignored thinking that couldn't possibly be the problem... But it was setting the engine into limp mode without any indication it was being derated. Btw, the slamming into gear is normal. When transmissions go into limp mode they default to maximum line pressure. This causes VERY aggressive gear shifts. These transmissions are some of the most uncomfortable for that. Good job at keeping an open mind!
Thank you Chrysler for making it easy to read codes on 96 and and newer vehicles. Cycle ignition key 3 times on and off and on the 3rd time, leaving it in the ON position, the dtc codes pop up on the odometer. That's how i keep my my 20+ year old Durango and Dakota running and my previous 4 Grand Cherokees.
Watching you cover so many topics, I have learned to look at everything going on with a car. AND visual inspection!
My daughter's car had a blower motor issue and all my research led to a wiring problem near the fuse box.
But, performing a visual inspection on the wiring in the circuit, the resistor had gotten so hot, two of the wires had melted together shorting the circuit.
A new pigtail connector and it's fixed! The resistor was fried, that was the original cause of the problem.
I HATE transmission shops. NEVER had a good experience with them. I learned though- when my 76 GranTorino's tranny quit- I went to the junk yard and got one for $100 (back in 79) - took me and my buddy a week to do the swap- worked perfect. Learned a ton. Had to rent a transmission jack- but that thing was amazing. Anyway- Ivan, you are amazing. I hope that customer didn't pay those other guys anything. A whole year down because nobody wanted to THINK... other than Ivan of course. What baffles me, why NOT replace the knock sensor?? The code came up on the scanner- the part is south of $100 and it's pretty much in front of your face after you remove the BAD battery. Even if it's a "no way it's the knock sensor" thing- you've eliminated a 'possible'. Again Ivan- just awesome. I'd DEFINITELY travel 3 hours to have Ivan look at a problem.
THANK YOU FOR FIXING MY CAR!!!! I missed it so much. The exhaust is a glass pack. It sat for so long and I missed it so much!! 😢
My pleasure Tori! Zoom zoom 😎👍
I'd drive 5 hrs for Ivan to fix my car. Unfortunately, I live in Oregon, and no Ivan or Eric O. in my territory.
I dont understand why they didnt replace directly the knocksensor stupid garage
Lesson of the day is ; Mazda engeneers build in a safety feature if knock sensor fails or noticed an abnormalty, the drive train should go into limp mode. Anyway excellent find Ivan.
8:12 "I guess anything is possible" is the ultimate wisdom in this field and every other field.
I remember I was diagnosing a car that had shift problems, maybe even had the same symptoms, and the code that was set in TCM was a) unheard of b) had no information about it on the internet c) there were codes stored in the PCM that has no relation whatsoever with the transmission or how should it shift. After almost 3 days of trying to figure out the problem it turns out that one of the codes in the PCM that was caused by a MAP sensor that lost a ground wire causing the transmission to go in some sort of limp mode and make hard to shift gears, exactly like this car with different sensor and error causing the problem. The car was a Renault, a french car and I will NEVER forget this car ever.
I seriously wish I could shadow you for a few weeks and watch you work. Its extremely impressive the way your brain works through some of these issues. Hell, i'd glady work for free the entire time. I legit have 26 years experience as a paid professional automotive tech but i couldn't hold a candle to what you do and am pretty envious of the level you're at in this field. Definitely one of my idols. No bs. And I don't have too many. Staten Island Keith is one. Mr Danner is another. Mr and Mrs O, Perkins, Brin Klein, Cody, Super Mario. Cuba, Mech Mindset. Steckler, Pete Meier, Jerry Truglia, Mike Becker, Bernie Thompson, and plenty more but its late and my brains slowing down so I apologize for leaving a few out. What I'd give to be a fly on the wall.
its not just Ivans gift of mechanical and electrical skills., its his control of emotions.. he doesnt seem to get angry or aggravated by most problems. he is able to clear the clutter from previous attempts. and focus. most techs experience alot of pressure and fear because you are against the clock. he is very even keel emotionally. has a positive attitude and is very determined to find the root problem.
Yes! All that was said is very true!
He's worked on old motorcycles bringing them back to life.
He's spent time in Russia where thinking outside the box was definitely required. Not sure how long.
Keith (New level auto diagnostics) took him under his wing for a week or so.
I believe he's an EE that was working on his masters and got tired of the 9-5 drag and went out on his own.
Ivan, did I miss anything or something needing correcting?
I am not sure shadowing him would help. He is a trained engineer who knows how to be analytical. Using all available tools including scopes, pressure transducers and the best scanners. He has built up large amounts of experience by taking the harder diagnostic specialty route and no employees rather than the common and repetitive shop track. His wife is a professional which no doubt allowed him time to build his strengths before he became as proficient as he is today. And the small things. The use of a notebook to record steps and measurements. Knowing how to use search terms effectively by guessing terms likely to be in the answer. Occasionally phone a friend. Finally he was smart enough to visit youtubers like Eric O and listen when Eric encouraged him to do youtube. Now Ivan's youtube income may surpass his customer income.
@@dans_Learning_Curve its also genetics.. his father was a nuclear scientist.. the apple usually doesnt fall far from the tree. Teaching people when they are young how to do deductive reasoning, utilize thier resources, and look at challenges as an interesting project rather then grueling work carries thru the adult life of the person. Ivan always says "this should be a fun case study". he has a different attitude. than your average Joe and is not so prideful that he is ashamed to ask for help at times.. he is smart enough to know that he doesnt know everything.
Just shadow him by viewing his videos is already great 👍
One of our 2003 S-10's would intermittently want to start out in 3rd gear. I noticed the alternator making noise and the scope showed problems with the rectifier bridge. Replaced the alternator and the transmission never acted up again! Great video!
I work for Fisher Auto Parts here in Michigan and yes we try to get the parts out the door in 4. Great video Ivan as always nice fix.
9:38 extremly lucky that the person asking that question actually followed up with how they fixed it instead of generic "nvm i fixed it" or "idk what happened but it fixed itself"
It is a good idea to check the alternator first. My 2005 Mazda 6 went into limp mode a few years ago and it turned out that the alternator was bad. I had the alternator replaced with one from O'Reilly's and it fixed the issue for about a month--until the car went into limp mode again. The alternator ended up still being the culprit. The problem is that at places like O'Reilly's or AutoZone sometimes the remanufactured alternators are not rebuilt properly. I learned that it is a good idea to have alternators and car batteries always bench tested at the store before buying them to spare yourself from future headaches. Hopefully this tip will help someone.
Get a Denso alternator from Rockauto, problem solved. Other aftermarket brands and sometimes even dealer remans are JUNK out of the box 😅
Ivan, another job completed. As I'm concerned about your safety, did I see you do that "test drive" without your seat belt on? We need you Ivan. :-) A loyal follower, mike
I’m an Aussie and grew up with belts, they are just built into our brains from kids. It really does hurt my brain to see so many Americans on so many platforms simply not putting them on.
Wow, well, all the trouble codes can be interrelated to everything. Damn knock sensor knocking out the transmission! Damn good fix Ivan! Great job fixing an hour of diagnosis! Wow unreal. I can't believe it lol
It never fails; customers bring in the car full of gas, if the tank needs to come out, bone dry if you'll need to drive it any distance.
THAT is so true! At least 2 customers like that come to my shop every day.
Yup! I worked heavy duty and if you needed to remove the fuel.tank or the crossover hose, the tank would be full. If you had to dyno it the tank would be MT.
Happens all the time at the bike shop I work at. Doesn't run? Oh let me fill it to the brim with gas
As the solution vs mechanic diagnostic history shows, people have a reason to bring a car in with no gas. It's a known and shitty practice that "cool" cars are "test" driven fast beyond normal acceptable parameters. A mechanic should simply ful the tank as needed and charge the customer per gallon used via trip odometer. Trust should not be required for any trades repairs. Logic, detailed, explanations that are observable and/or replicable should be standard practice before applying repairs. Issues with process addressed as needed throughout that will add to the bill. I understand there are exceptions to any rule, however... Good mechanics or tradesmen are now the exception vs standard.
Yup! K.I.S.S rule first… just a little farther info. Knock sensor was retarding the timing to prevent engine damage. Also putting trans in limp mode (which we know lol) 3 gear is most likely a 1:1 ratio. So putting as little strain on the trans too. That’s also why reverse worked. Direct drive (input and output shafts locked together) inside the transmission. Just turning in opposite direction. Good video!
But starting out in 3rd gear shreds the poor torque converter...not to mention the super violent shifts into R or D LOL!
Another amazing story with a happy ending. Thanks, Ivan!
This comfirms that in auto diagnostics, every day is a school day. No matter how experienced you are. Great job . Look forward to the next one!
Scandalous! All of it. Except the 15 min. repair and placing a new battery. Well done!
You r a rare real gifted mechanic. Thank God for your gift!
Super stuff, really enjoyed that. All of these videos just reinforce my view that manufacturers have made cars so complex they are almost unfixable making them technologically obsolete so we need to buy another one when anything goes wrong. Heard hundreds of tales of cars and bikes taken in to dealerships charging top rates and unable to fix them.
Great pickup Ivan! Mazda should really issue a TSB or some sort of instruction to alert mechanics (including their own) of this issue that can cause the transmission to go into Limp/Safe mode. It is way out of left field that a knock sensor would cause this transmission issue!.
Ivan. Logically. If the engine indeed had a slight knock.
Would it make sense to try to save the engine and transmission. That's why the transmission was in limp mode?
Because I've had customers had a noticable knock and they were revving the engine even more 😂
Saying o...it's been like that I'm just driving it till it gets worse. Duh
Really this shows that DATA is important... if manufacturers listed the CONDITIONS that can TRIGGER a limp mode... then you can just look it up but no they all have to be secretive about their damn software then years later they just act like they never made the car and no-one can see the data it's all so stupid
Stupid f*ks...take names.
When you said it had a knock sensor code I was betting that was it as you have said in the past on newer vehicles anything can cause all sorts of problems to show up on the CAN BUS HIGH/LOW.I bet the customer was pissed .Cheers another good video.
That gives us all hope! Check that everything else is working right before entering the wrong rabbit hole and lining up the parts cannon.
Crazy how the knock sensor can cause the transmission to go into Limp mode. Great detective work and fix!
I got to admit I wouldn’t have thought it would have been a knock sensor good video
I bet your neighbors were all impressed by that exhaust!!! 😆
I hate people that do that.. its a fricken station wagon its not a race car
@@zippythechicken why not both? ¯\_(ツ)_/¯
This one was whisper quiet compared to that yellow straight piped VW GTI 🤣
@@caseyjames9570 no its not a chevy nomad ... your mom gave you her station wagon so you would get out of the basement.. its not a race car HA!
@@zippythechicken ...You mean when people either straight pipe their rice beaters or add a fart can to make it sound louder and cooler.
Definitely some questionable programming in that TCM software to go into limp mode for a fault like that. I could maybe see if they were trying to avoid the engine pinging or something, but I'd think locking it in 3rd from a stop would only make that worse..
Reminds me of the GM vehicles which would keep the cooling fan running all the time with literally any DTC set.
What's even more interesting is the code description does not mention that this happens when set .
@@keltecshooter And there being no code in the TCM saying it's in limp mode because of a dependency on a fault code in the PCM.
Meanwhile the PCM wasn't in limp mode at all...
isnt the simplest fix often the correct one. Just cant fix what you don't understand how it works. Great work! That is how my apprentices are taught to think.
Always such great content. I would have never thought that these two things were interrelated. They were so lucky to bring it to you.
The PCM firmware was programmed to put the TCM into limp mode with a knock sensor fault. Likely the best approach is to have not codes ever. If one pops up then whatever change in the vehicle behavior occurs is related to the code.
@@SirDeanosity Yes. Thanks for the information. Always glad to learn. There are some smart people out there. I am not necessarily one of them so I am still driving my 1989Honda CRX HF that I bought new in Jan. 1989. It has over 377,000 miles on the odometer and has never been in the shop. The simplicity of the car matches my skill level perfectly. I don't have any power windows or seats, no airbags, no traction control, lane assist, power mirrors, automatic transmission, cruise control, infotainment system or anything else. I don't even have a cupholder. It was, and is still, basic transportation that has never broken down on me once and I have kept it that way with just preventative maintenance. Not one drop of oil has even hit the ground. It still blows 40 degrees through the center vent with the air conditioner on which is a godsend here in the deep south. It is a trusted piece of history to me and will never be for sale. I love the PHAD channel for Ivan's great diagnostics and how often he is able to fix something with no parts required and his sincerity and honesty. Have a great day.
had an 06 6s (v6) and it was a love hate, Loved driving the car, comfortable, good torque. Hated the front seal and valve cover (replaced) oil leaks and most of all the garbage aisin 6 speed transmission. in 140K the engine never gave me any real issues, but I did have 3 replacement transmissions under warranty. Trans would flair between shifts with at full operating temps. On the highway, peddle down it would buck between gears felt like the powertrain was going to fall out. Glad Mazda is wholly owned again, love my 17 Mazda 6, no a lick of trouble.
There are actually some really smart ingenious people out there, and luckily most of them are willing to share.
A few years back my W140 S-Class Mercedes would jump out of cruise control on the motorway, ABS light would come on and power reduced.....
FIX.... a new brake light switch on the brake peddle.
Go figure.
So you are right, fix what is broken on modern cars, the faults may all be interlinked.
Good troubleshoot👍🏻👍🏻
Nothing like when they throw the parts cannon at it⁉️💯😂😂😂
Toyotas had an issue similar to this. If knock sensor faults were set on the 3.3L v6 engine, the transmission would shift through all gears fine the first time but would not shift into overdrive or 4th gear afterwards. Would need to shut the car off and restart it. Replace the knock sensor and sub harness, shifting would return to normal.
What did we learn? There is a software bug most likely in the transmission controller. The PCM will broadcast the P0328 fault to the other powertrain modules on the bus. Putting the transmission in limp home mode will not address engine detonation. The PCM will address a bad knock sensor by changing the spark advance to limit the chance of detonation. The only strategy that I know of that could cause a system wide reaction to a bad knock sensor is if the PCM strategy used active knock. Which is a way to enter a knock condition given a set of engine drive cycle parameters to test the system and other things like fuel octane estimate. However, when a knock sensor is bad or the connector disconnected, active knock should be disabled. Perhaps there is a software update for the TCM?
For a transmission in limp home mode for an extended time, I would do a fluid and filter change. Perhaps not a complete transmission flush unless the fluid looks and smells bad. So, at minimum, just the fluid in the pan and the filter. But, be warned dropping the pan may not be easy and in doing so you may require a new pan gasket. However, by inspecting the pan and any debris you can get a feel for if the transmission has been abused by limp home mode. Perhaps the transmission shop already changed the fluid and the filter?
If you do a test drive after limp home mode and you feel a TCC shudder or an overdrive shift shudder, then replace the fluid and filter. If you are doing a complete flush you could try using a synthetic blend transmission fluid from Mobil 1 which I have found has a slightly higher viscosity than most factory fluid which helps eliminate shudder if you do a complete flush (change).
Ivan, future reference herre with Mazdas like this one that have Ford engines....and yes this is a Ford V6. If you want OEM parts, call the local Ford dealer. I don't know how many times I've had to contact our local Ford dealer to get parts that Mazda says "we don't have that".
That's helpful! Are some of the 4 cylinder engines also made by ford in Mazdas?
I remember Ivan's video with the mazda rebadged ford escape where one subframe bolt was a FoMoCo part and had to be sought from a ford dealer
BRAVO Like you said fixed what's broke. You also revealed big secret on internet searches. KEYWORDS people. I work in I.T. and shade tree work on cars. (Hey a computer is a computer) Doesn't matter if it is on your desk or in a car they function is the same. Specific keywords like Ivan showed will often give you the answer you are looking for.. Nice job my friend.
Made me smile Ivan.....You said "as good as new" and the head lining was flapping around like a main sail on an ocean going yacht lol.....Great video again matey....Saludos desde Esaña mi amigo....
Just WOW! Who would have thought it. Unplugged too. Top job Ivan. 🙈👍
I can see how someone can decide that the knock sensor is not related to the trans issue. It doesn't make much sense really. Great job. thanks!!!
I faced similar in a 2013 Toyota Venza... Knock sensor codes and transmission goes gaga... However not exactly in limp mode, but give a violent jolt between 2 and 3. Nice job as always
That was awesome! I never would have thought it would limp the transmission.
This is how i fix 90% of the cars i work on seriously, its not hard do your research use your options, otherwise great work again ivan!
Wow thinking outside the box, that is your forte Ivan! Cool beans!!
I diagnosed a no comm for tcm, missing certain gear, sticking.
Bought the car, Mazda 5 , 2008 van, 147k miles from owner for $750. Ordered a refurbished tcm from California. They were plug and play.
DONT mount it on the transmission, rather on the firewall with a couple zip straps.
The heat from the transmission causes this issue. The transmission would slam, hit into 3rd as well.
Replaced tcm, cleared codes and has worked great since this last year.
Very cool! I would love to see the program logic on how the transmission goes into limp mode because of a knock sensor. They must have had a reason. lol
Wow unbelievable. You sir have excellent logic skills!
Watched this before leaving for work this morning. I told Gloria it was the knock sensor as soon as You said it had that code! How did I get so good? (Lucky for once) There is nothing wrong with a quickly once in a while! 👍👍🇺🇸🇺🇸
What a crazy diagnosis. What was the transmission shop folks thinking ! Not transmission related but it fixed the issue. Thanks for sharing !!
Wow I have had some problems cross between models but never something quite this crazy! Thank you for the video and info!
On Japanese cars, the transmission is always getting a "torque signal" from the PCM/ECM, so it can "prep" for shift's. It's one of their secrets for smooth shifting and reliability I feel. lol
The bad knock sensor meant that the PCM couldn't properly calculate the torque signal, as it didn't know the knock condition (which would definitely throw the actual torque off of the signal, if the engine was knocking and the PCM couldn't tell) so it was likely shutting off the torque signal.
It wasn't until 2010 or so when the OEM's thought to have the no torque signal condition actually trigger a readable code from the TCM.
So as you said at the end of the video, always fix codes in other modules before chasing specific rabbit holes.
Also reminds me of an issue I saw when I was in college. Had a UPS (battery backup) in our lab which would not communicate with any of the computers in our lab via serial port/RS-232. Since I was one of the better students and had all my assignments caught up, the professor put me on the job as classes for the prior two years could not figure it out either.
So, I noticed since they had us wipe the lab computers so often, they were just using drivers built into Windows XP. So I just started updating drivers one at a time and trying the communication, starting with anything that *could* influence the serial port. Nothing there. So moved on to every other driver. As soon as I installed the video card driver, it started communicating.
On the next lab computer, I installed just the application for the UPS and the video card driver, and it worked on that too.
TL;DR: I once had a video card driver influence how a computer communicated to a battery backup via an old serial port (like USB before USB was a thing.)
Amazing no one did the parts cannon and replaced the knock sensor and fixed this prior to you. Incredible.
People are worried about throwing parts at a car if there is a serious issue I can understand that. Not sure what that part cost. I would had that replaced if it were under 100 dollars with labor or if I could had done it myself.. Great Video and Excellent job.. I am waiting for Vehicles to go into limp mode for a low tire
Ivan, I think all that car needed was a nice day. Great to see you enjoying the weather while doing what you do. Makes us all feel good! Thanks for Sharing!
I have not run into this problem before. That's something good to know though. But I have had a Ford Taurus V6 no start because of a bad ECT sensor. That was a bit misleading. I have found that sometimes it's worth looking into those little issues that are seemingly unrelated.
Love your thought process. Great job Ivan!
Honest man . wish more PPL like you
Good problem solving. Thank you. We had an oil pressure sending unit failure send a 2019 Honda Pilot into limp in mode.
Wow, what a fun little wagon. I’m going junk my M3 Hatchback/station wagon when the transmission fails soon and I’m going to find an M6 Hatchback/station wagon to replace it.
Well done Ivan. As I always say: the answer is out there, you just need to find it - power of the internet.
That's crazy. I never would have dreamed a faulty knock sensor would put a computer in limp mode.
the knock sensor is for what ..... to tell the computer of a problem ...... the computer can only know /respond to what it is told ..... that's my take on it .... me : not a mechanic
@@ivanolsen7966 the knock sensor is to detect engine knock (fuel knock) so it can back off the ignition timing. It's part of a feedback system, not a problem detector.
Forcing transmission limp mode is extremely odd behavior for that sensor. Engine limp mode can be expected, but a perfectly running engine and only the trans in limp mode? It's very odd.
@@volvo09 Exactly
@@volvo09 Perhaps it is just tied into the limp logic? Just a thought.
You will be surprised that in newer cars, even a bad taillight bulb will trigger the limp mode lol learned the hardway
Honest , smart , funny, you are the man.
I agree with you about the availability of information on the internet being helpful, but I have also seen a couple of negatives. I have been a technician for over 30 years and have trained several techs over the years. I have seen young guys who would rather try to find their answers with a Google search than actually learn how to diagnose a problem.
Same thing on an 03 Taurus. Stuck in 3rd gear. 2 transmission shops said it needed new transmission. 3 egr codes and 3 transmission codes. Found that egr and transmission shared same circuit and wires were melted on egr pipe. New fuse and a quick wiring repair and the car was fixed after 1 year of sitting.
This one didn't surprise me at all---anything that puts the car into limp-home mode can impact other systems. Parts required, but not expensive ones = win
I had a 2002 VW beetle. It was throwing ABS error codes. Car under warranty. The dealership replaced ABS sensors 2 or 3 times. It was 20 miles round trip to the dealer. Driving me nuts. I called VW customer service, gee the multi-pin connector from the engine compartment to get wiring through firewall, had been sprayed inside with insulating foam only meant to keep water out of the inside of the car. Factory error created a short for the ABS system. It is nice to see that we have dedicated techs that can actually diagnose a problem. VW bought the car back from me under the California Lemon Law.
Crazy I have a 2007 mini cooper with a CVT car went in to limp mode due to a tach having and intermittent com problem , I noticed the tach blink before the limp/EP mode , Found one post on a forum contacted the guy to confirm we had the same issue i disconnected the tach and drove car with no issues I spent weeks tracing wires and checking modules Great job
Somehow get onto that original guy/gal and you thank them profusely.
One time I searched you tube on how to reset the oil change reminder on my car. I found a 6 year old vid and said thanks heaps in the comments and the vid poster was very happy that he could still be if help that many years later. This tranny vid is from 2011.
I have fixed countless transmissions in limp mode but have never heard of this one before. Must be a secret known only to certain Mazda Techs and engineers. Can't believe there are no factory diagnostics for this or a pairing code set in the TCM. Hopefully Ivan you post this tech tip in Alldata.
Thanks for the video Ivan great job 👍❤️❤️ it. My Subaru outback had a Abs code and O2 bank 1 and Temp sensor. Fixed the Abs code and all good.😅. Take care of yourself and family and be Blessed ❤️❤️❤️.
Great Insight, You Video has impacted a whole lot to me
That is interesting that it didn't set at least a generic po700 or at least something stating it was indeed in limp home mode. Kinda makes me wonder if you could recreate the same issue, by perhaps disconnecting another major sensor like a CTS?
Thanks, man! Great info! It's really entertaining watching your videos, and the stunningly rich rich source of information, just AMAZING!
Hello from London. My car kept going into limp mode with similar transmission issues (automatic box stuck in 3rd. and illuminated engine light). I was dreading the cost of a new gearbox but was advised (by telephone) by my dealer to check if the petrol filler cap was tight. I thought it was, but he suggested removing it, blowing hard into the filler, leaving it for 10 minutes and then replacing until I heard two or three clicks. Turned out that the sensors had detected fuel vapour which wasn't being dispersed properly! They had seen several owners of my model with the same issue.