Brilliant diagnosis Eric....aren't you tired of aftermarket companies producing junk that can cause you to go down rabbit holes like in this case?? Thank goodness you have the experience , service info and gut instinct to know what is right...keep up the video's bud.
@@jblyon2 no..the problem is, before chevy or toyota or whatever oem seller buys the same parts from a manufacturer..could be the same part NAPA or standard sells, the part will get QC tested. The testor passes the parts that are closest to oem spec. Then the rest go to the " undersellers, or acme cheap discount auto parts inc
When you put that calibrated resistance tool on the circuit and got the proper expected feedback from the pcm, I said “dang, that’s cooler than the other side of the pillow!” You never stop learning me stuff, Mr O!
Eric is a very humble person, he always says he’s not very good at the software side of things, yet he shows very detailed videos like this one that goes in to depth on how he came up with his findings. Ive learned a lot from this channel, and always look forward to new videos!
one of the best vids u have done, because it goes to the heart of not overlooking a simple sensor that could be junk even if its new, great work as always, thanks for posting
Eric, you have taught me so much over the years. I would replace a part and call it good. You have shown me the way of a true master. Trust but verify. I am so grateful for the time and effort that it takes you to produce a video and share your knowledge. Much love my brother, you inspire!
I just had to post that I think this guy is the most brilliant car mechanic on TH-cam. I’m not joking, I’m in awe every time I watch one of his videos. Guys like him are rare, it’s like a natural intelligence. An unusual ability to understand and manage complex problems. I feel like such a mental midget watching this guy. He ends with “If I can do it, you can do it” but that’s simply not true. The only time he ever lies in his videos.
Eric, we'll say 40 years ago, I built a very strong 454 for a hot shot driver in his 78 one ton Chevrolet. Put a new standard temp sensor on and anytime he got over 60 mph and turned the a/c on the temp would climb to 230 degrees. It was using a quart of oil every 500 miles Pulled it apart, took l out the chrome molly ring and went back with steel rings trying to dry up the oil usage. Still overheated. Finally put a thermometer in the radiator, showing @ 160 and the gauge at 210. It would not get hot enough to seat the rings. Put the old senor back on, temp got right and got the engine hot enough to seat the rings. no telling how many hours and money lost trying to figure out it was just a new bad sensor. I feel your pain.
I just wanted to say two things. 1) I'm sure I speak for others in saying thanks for all the hard work you do in making these excellent videos. 2) I hope you're making a very nice income from TH-cam for all this hard work!
I read through most of the comments and didn't see anyone suggest this, but being a heating/a/c guy, I would suggest that to be absolutely sure of the internal temp of the sensor, soak it in an insulated cup of crushed ice/water. This would put it at exactly 32 degrees and remove all doubt as to the actual temperature of the sensor.
The change in resistance vs temperature is logarithmic for those thermistors. That chart you showed has enough data points to plot a log curve so you pick off interpolated values of resistance for any temperature. Also you could make a more versatile dummy thermistor test tool by putting a 100 ohm 10 turn pot in series with the one you already use. Allows for finer adjustment of resistance values. Might be useful for those picky GM drive cycles. By the way, the multi-turn pot I saw you using should be accurate enough so you don't have to confirm all the time with an ohmmeter (saves time).
You still need to check the resistance with a meter to get accurate results. With a multi-turn pot you can set the potentiometric resistance ratio very accurately, typically 0.1% error, but when used in rheostat (variable resistance) mode the errors are greater due to the tolerance of the end-to-end resistance, typically 5%. Directly dialling the resistance value could have resulted in an error of up to 5.1%, which wouldn't have been sufficiently accurate for the testing that Eric O was doing.
I always learn something watching your videos. I was in IT for over 30 years, jack of all trades doing Cobol programming, newer languages, interfacing PCs and Mainframes, and PC repair. Your logical approach is the same as is used in repairing PCs OR in finding a bug in a program and I'm always impressed with your clarity of thought. Keep up the good work and I wish you continuing success!
I ran into a similar issue with my Holly sniper. The temperature reading was off with the sensor that came with the unit. I ended up purchasing a Delphi temperature sensor and that cured my problems. Just to let you know, there are calculators on the web that will give you the exact ohms reading to temperature. Great job and always great videos!
Seems about right. Cheap chinesium sucks and costs the customer more. Wish i had a mechanic like you here, woulda saved me tons of money. Thank you Mr. O!
One more reason to use OEM parts......less expensive in the 'long-run'. Delphi used to be owned by GM, so the Delphi parts should be 'compatible'. Another great diagnosis!
When troubleshooting customers RV appliances, the first question I would ask is "What is it doing or not doing?". Always got a thoughtful concise and informative answer from the customer. They are your best source of info and always know simple facts like "When I turn on the thermostat, nothing happens", even though they don't know the technology behind it.
Lots of good stuff here. My Subaru ej25 was running rich enough to wreck the cat. The coolant temp sensor was bad. The replacement stanpart was not calibrated ideally. Oem from a dealer solved it. Reducing part numbers by "retionalizing" their inventory could lead to unfortunate compromise being made by hasty penny counters. Their gain was my loss.
The coolant temp diagnostics was spot on. A new GM sensor would have shown the difference. The vehicle sitting overnight proved that. I found graphing the cat monitor and watching the digital readout will work. My wife 06 Sorento proved that when I was testing the cat monitor. That one was intermittently working then it would "track" the front B2S1 sensor, continually doing this cycle. Good call on the CTS, unfortunately 2 bad cats will ruin a good day. Good one Mr. O!
In Philly 2000 an up can have 1 incomplete. You just have to get the evap to go befor the cat . Once the evap is ready it can have codes for the cat but the light can not be on . So a key cycle would turn off the light and try the cat test again . Just have to slip it through then .
Just moved to a state that eliminated vehicle safety inspections. At night it’s not uncommon to see 3 or 4 vehicles with faulty headlights or tail lights. Taking a walk thru a parking lot reveals numerous worn tires.
What we have here is a qualified experienced automotive mechanic dealing with the intrusive electronic components that want to monitor/dictate everything related to a poorly designed system. Automotive engineers 👎 Parts designers👎 Old school mechanics 👍 And if you happen to get in to a collision, your car will rat on you big time. Thanks Eric, you are helping me go through another crappy Canadian winter.
How I look to friends and family with a scanner in my hand: Wizard! How I feel with a scanner in my hand after watching an Eric O vid: a 2 year old holding vice grips
Great video Eric, Getting to know the drive cycle monitors takes some time. There is a lot to it. Good electronics diagnosis but checking the sensor characteristic. Hard to believe they actually make them wrong. I have actually designed temperature sensor gauges and had to characterize a thermistor. When at Cosworth they actually built the look up table with the actual sensor they were going to use thereby eliminating possible manufacturing errors.
@@billrimmer5596 Not anymore, now in Springfield New Brunswick Canada. Miss old England but it is so difficult to live there unless you are very well off. Just help fix stuff here now mostly electronics and cars.
that little potentiometer that comes in the AES wave connector kit is a go-to for me. I've had a number of situations like this one where new part doesn't solve the problem and I've been left scratching... further emphasizes that a known good, is good! Thanks as always Eric!
The most successful advertising is providing knowledge, skills, and attributes when solving problems. Eric nails it without embarrassing people too much. He does make people wonder why dealerships don't do deep problem solving. I guess the answer is not enough ethical standards. It's one thing to throw parts at a problem to solve the problem, but throwing parts at a problem and still not solving the problem is criminal. Mistakes are normal but trust is the most important result.
A couple of years ago I bought a Standard MAF for my Ford when trying to diagnose a P171/174 lean error. I immediately got a sensor failure message upon installation and subsequent drive cycle . It went away when I put the original Motorcraft MAF back in. I learned a valuable lesson that day. Even if the part is new, it can be crap. Thanks for reenforcing that message Eric - buy OE parts whenever possible folks!
When I’m bored and want entertainment I watch other mechanics you tube videos, when I want education , I watch you videos. Not knocking other mechanics content but being a mechanic over 45 years but now retired I find I’ve been there done that. Some of the tougher jobs I catch myself saying stuff like , “ wish I had that tool or that looks easier from when I did that” . Your videos seem to be the jobs no one wants or gets in their shops.
I love watching you and your testing equipment go to work. Reminds me when dealer could not tell me why car would shut down after 10 minutes of running. Always happened to the wife never me until 1 Sunday morning. Waited 15 minutes cracked right up, got it home, got my Dodge engine book and voltmeter. It was an 84 Dodge caravan, 4 cyl.; there was a motherboard inside the distributor for lack of better name. When it got hot it would crack, when it cooled down it made contact. The dealer shouldn't have found it in 20 minutes, took me 4 hours and a bunch of fancy words directed to Dodge.
17:00 About how the PCM measures the Temperature: the Sensor line is connected internally to +5V through a Pull-Up resistor (typically something like 2kOhm). The sensor completes the circuit to ground, forming a potential divider. The PCM then senses the voltage at this connection, which is then translated to a temperature via a lookup table.
That clicking is a blend door actuator. The ones in my Impala make the same sound when going bad. It's turning all the way in one direction and trying to keep turning, jumping teeth on the gears inside the actuator
Well done Eric, I am surprised that the Standard brand is off, their parts are usually pretty fair. Just shows how much of a difference from part to part.
This is what happens when private equity companies buy out iconic brands. (Covers almost everything in the automotive aftermarket) I actually spent the time to hunt down shelf worn NOS Blue Streak parts (Standard's 'premium' brand) when I did a recent tune-up
It’s unfortunate aftermarket stuff does not work better than it does. I chased my tail on my personal car for a lean code. 02 Sensor was replaced with Ntk on a Gm. Truck required oem Denso to fix it and turn the cel off👎.
Great job Eric! Working for Chrysler from 1979-1994, every once in a while we would get some sensor out of wack for the old Lean burn system. Usually, it was caused by someone not understanding how everything works together so when somebody turns a screw the wrong way and leaves it things happen a downward spiral from there. I hated to get rebuilt computers as that was the norm then. To me, dealing with a lot of vehicles new and old, NAPA has quality problems on their Chinese parts! I always try to get factory parts if available.
Great video as usual. It would seem that in the race to become a go-to aftermarket supplier they are trying to cover all makes & models, but failing to get each variation of a part to be as good as the OEM. Your logical approach serves you well - keep up the excellent work!
I’ve also learned from experience, at least for GM’s. You will not complete a drive cycle, unless you use the key to start. I was using my remote to start and I couldn’t complete a drive cycle and somebody told me no try using the key after it sat for eight hours.
Nice diagnosis. Most shops would have seen a new CTS & looked elsewhere. I'm retired now but it is so enjoyable watching you diagnose & work on cars. Just had hip replacement surgery & I'll get back at it but on a limited basis for some of my older customers but now the priority is bass fishing & tournaments. Thanks again for enjoyable videos!
Hello Eric, possessor of Associates Degree in Electronics here to put in my 2¢. You had mentioned that you don't know how a PCM handels input data to calculate stuff and produce output to whatever it's sending the signal to.... BUT you wish you did. Experience tells me that the only people that know that stuff are the clowns that engineer it because it's proprierity information for a peoprierity system. Sure, there are techs and repair people that are curious enough to study it and find out what works, but It's not like you can take a class or something to find out. That's a really good plan used to determine that BOTH temp sensors were bad parts. Unusual circumstance calls for a solid plan and you had it. You are a really good repair type person/ auto tech. I don't know what you charge your customers but they do get their moneys worth on these type of repairs. A combination of knowledge, skill and experience.... it's too bad that there aren't more guys like you in the repair business. THEN we would feel like we are spending money wisely.
Wow! You're thought process is so impressive! I love that you share that as well. It is sad that the places that manufacture items that are supposed to fix things make them unreliable, that dang BOB guy! Thanks again for what you are doing and tell Mrs. O. to keep you in line!
Mr Eric o these is a great video. This content was so difficult that I was confused trying to figure what was going own. Until you explained the whole process. Thank you for teaching us. Again great content keep up the great work.
I’ll never forget the car you worked on where the power steering pressure switch was bad and making the computer say the evap was bad. You may be able to do it but I can’t and don’t want to.
As a NJ state emissions repair and inspection station l have run in to that very repair many times. Good diag as always,shame about the crappy after market sensors though. Some customers don't like hearing they have to spend more money to get the sticker though, especially for new cat's. "It's only a stupid light". How many times we've all heard that one! Thanks as always for great content Eric.
watching the O2 data showing it test the cats in real time was neat, reminds me of when I had a cat replaced on a buick to rid the 0420 code. few months later the light was back for the same thing. ended up watching the data while I gave er the beans and the rear sensor settled down. I just let it clear the light on it's own to be sure it was cleared.
I am glad there are people out there that understand this stuff so my vehicles can get fixed properly. But I wish there were more like you and my auto tech guy because there are just to many shops out there that should just doing oil changes
My '97 F-150 would constantly go into limp mode. Ford dealership said it's a bad head gasket. Didn't believe it. I purchased a new sensor from them. They sold me the wrong one and it smoked the temp gauge. Temp gauge no longer worked, but it solved the problem, no more limp mode.
The linearization circuit in the ECM for a NTC Automotive Thermistor has many different possible configurations. The most versatile is a VREF resistor voltage divider with the sensor on the low side (across the low side resistor). This provides good linearization adjustment and effective failure mode detection (sensor short or open). To diagnose the entire circuit you would have to know the ECM divider, VREF magnitude and the Thermistor resistance table (Resistance vs. Temperature). The ECM design team produce good results with the linearization circuit but the measurement errors (sensor sensitivity and ECM A to D resolution, usually the small VREF errors are not a factor if the measurement is ratio-metric) do increase as you move out to the temperature extremes. From a legacy standpoint for GM the Intake Air Temperature and Engine Coolant Temperature NTC Thermistors are of the same basic type (thermistor pellet), meaning they have identical Resistance vs. Temperature tables, but the response is very different because of how they are packaged, the Air Intake has a plastic body (fast responding) and the Engine Coolant has a metal body (slow responding). If the harness is good and the ECM VREF is good, then it has to be a problem with the sensor. In production you will find many different sensors (thermistor pellet) of the same type but with slightly different characteristic curves of around 5 Degrees C from one variant to another. If you put the wrong pellet into the sensor you are trying to make it will show a skewed value when used in the application, but other than the skewed reading it will look like it is working. When working with an Automotive Thermistor supplier the characteristic temperature curves provided to the OEM (General Motors) are very accurate usually with a resolution of 1 degree C. If you have this detailed graph you can very easily verify that the sensor you have is producing the proper output at a given temperature, but unless you know exactly who makes the sensor it can be difficult to find on the web. The OBD-II EVAP and CAT monitors usually require two drive cycles, and as stated in the video, meeting the drive cycle criteria is a challenge because the conditions to run the monitor test are very specific and complex. Also, if there is a failure it can take two drive cycles to register the errors via the Check Engine Light (MIL). If you have a scan tool you should see a pending OBD-II code related to the system in question before the MIL light is on. The HEGO Heater monitor usually requires two drive cycles to complete, even if you open the heater circuit, which we know the ECM is monitoring, the MIL light will not come on until two drive cycles are complete. Which to me is a little strange when the circuit is obviously open. I guess what I am trying to say is the monitor criteria is not always logical, but designed to meet the spirit of the OBD-II requirements as interpreted by the OEM.
I can tell you from past experience (and a box of "aftermarket" sensors) with my 98 Jeep TJ, that whenever you replace a sensor, make sure the replacement is OEM or a "known good" replacement. Just because it is in a new package, looks exactly the same, plugs in, and may seem to function as intended, does not guarantee the PCM will accept the data it relays. Chrysler products are notorious for rejecting aftermarket parts and mine is a 1998 (with a few monitors), so I would think that they only get worse as the number of finicky monitor parameters increase. And from what I see on your channel and others, finicky PCMs are not exclusive to Chrysler. Great vid, Eric!
your diagnostic, and knowledge skills are steller. i repaired heavy equipment and cranes from 1972 to 1996 cat dealer and fed shipyard. the era of NO computers. it was not important to know everything. but your succes depended on knowing where to get information. now that need is 100 fold. and you just hit it out of the park consistantly. kudos!!
I appreciate your instructive videos. I will also say that I have had similar problems with NAPA parts. I guess like everyone else, they are having problems with the suppliers.
If you monitor the coolant temp voltage pid you could just short the coolant temp sensor. If the voltage goes to 4.9-5 then from the connector back to the pcm should have good wiring. Aways a great diagnostic session with SMA. Very through Eric.
Eric finally gets a V8 Trailblazer after all these years!! I have an 03 Envoy that also has the 5.3, but apparently 03 and maybe 04 used the older truck computers
Eric, Outstanding video presentation. Really appreciate how you break things down and insert the small bits of information that give the viewer a extremely clear understanding of the subject matter. Thanks again,
Using a resistor box of some sort (potentiometer or decade box) to replace the thermistor is always a great way to find out if a system that uses a thermistor is properly representing the 'temp vs. resistance' value of the thermistor . The important thing is to know what the 'temp vs. resistance' value is supposed to be for the thermistor application because the computer is going to be scaled to a very specific range of resistance vs. temp. As in this case the values of the sensors were wrong. Not sure if it was just the wrong part labeled as the right part, or a horrendous job of quality in manufacturing the parts. Good video and provides food for thought. Could shave hours off the diag.
Years ago I ran into this working on a JetSki pulled two new fuel sending unit off the shelf both were bad pulled one out of a other customers key everything work like a champ
Would love to see many more videos on Drive cycle monitors. Your viewers in CA would watch every one! Those are the bane of our existence in our state!! Thanks for the informative Vids!!
big help for me Thanks Eric . my 06 chevy express 3500 has been giving wacky engine temps for a couple years. I replaced the sensor and still the same. You gave me a lot of great insight and info. I really like watching great diagnostics at work. You da man😉
At least it was showing fantastic oil pressure on the gauge during your test drive. As Derek on Vice Grip Garage might say, “that thing has ALL the oil pieces, perfect.” 😂
If you have at least 3 data points of temperature vs resistance (which you do in that chart) you can use Steinhart-Hart equation to calculate the resistance at any temperature, or vice-versa. You can build this in Excel if you want and have tables for all the common sensors, assuming they are NTC thermistors.
Volkswagen actually wants to contact you. They are also trying to figure out how to disable the drive cycles but only when they are being emission tested.
At standard atmospheric pressure you can make a thermometer calibrating water bath with ice cubes. If the ice is the majority of water, the water will remain at 32 F or zero C. until the ice is melted..similarly. all boiling water at standard atm. pressure is 212F or 100C
Yesterday I ordered a hub for an ‘01 Tahoe and AutoZone sent me the correct box but inside was a bearing for a Buick Century. Yes this is the BS we have to deal with on a daily basis…
It's good to know that I live in a region that doesn't require this kind of vehicle inspection. But on the other hand it could be a migraine if you never know your vehicle might have an issue like this. Being former military I know periodic inspections, while a pain in the woohoo, can often find an issue(s) before they become catastrophic. Where I live that is when you know you have an issue and the darn thing won't run or won't run very good.
As a fellow tech for over 20 years, ny first thought was a brand new sensor in the head and another brand new one from napa, both aftermarket and both reading incorrectly, was to get an oem one to test.
Excellent video!! These are the best types of videos. Your very intelligent, and a Excellent mechanic/tech. Your costumers don't know how great they it,having you as their mechanic!!!
I had that same problem with my ford 12 or so years ago junk new napa sensors. got one from the ford dealer worked haha so from then on I dont use any aftermarket ones. crazy how picky the specs for calibration are another great video from you man cheers
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Brilliant diagnosis Eric....aren't you tired of aftermarket companies producing junk that can cause you to go down rabbit holes like in this case?? Thank goodness you have the experience , service info and gut instinct to know what is right...keep up the video's bud.
Dont think of it as junk, but inexpensive stuff that couldnt pass a strict quality control test
@@pootthatbak2578 That's business 101. If too many of your products can't pass quality control, just get rid of quality control. Problem fixed!
@@pootthatbak2578 not always so inexpensive........
I’ve learned. Anything electronic buy OEM
@@jblyon2 no..the problem is, before chevy or toyota or whatever oem seller buys the same parts from a manufacturer..could be the same part NAPA or standard sells, the part will get QC tested. The testor passes the parts that are closest to oem spec. Then the rest go to the " undersellers, or acme cheap discount auto parts inc
When you put that calibrated resistance tool on the circuit and got the proper expected feedback from the pcm, I said “dang, that’s cooler than the other side of the pillow!” You never stop learning me stuff, Mr O!
A potentiometer! Very useful in automotive work. He used that to rule out a fault on the PCM side
You've said it so many times. " Just because it's new doesn't mean it's good"
I prefer used parts because they have been tested.
Especially with the junk ass offshore parts we get shipped nowadays you cant trust anything.
I enjoy hearing you think out loud to your approach to these challenges.
Eric is a very humble person, he always says he’s not very good at the software side of things, yet he shows very detailed videos like this one that goes in to depth on how he came up with his findings. Ive learned a lot from this channel, and always look forward to new videos!
What a great way to start the day, a new South Main Auto video!
one of the best vids u have done, because it goes to the heart of not overlooking a simple sensor that could be junk even if its new, great work as always, thanks for posting
Thanks 👍
Eric, you have taught me so much over the years. I would replace a part and call it good. You have shown me the way of a true master. Trust but verify. I am so grateful for the time and effort that it takes you to produce a video and share your knowledge. Much love my brother, you inspire!
I just had to post that I think this guy is the most brilliant car mechanic on TH-cam. I’m not joking, I’m in awe every time I watch one of his videos. Guys like him are rare, it’s like a natural intelligence. An unusual ability to understand and manage complex problems. I feel like such a mental midget watching this guy. He ends with “If I can do it, you can do it” but that’s simply not true. The only time he ever lies in his videos.
Eric, we'll say 40 years ago, I built a very strong 454 for a hot shot driver in his 78 one ton Chevrolet. Put a new standard temp sensor on and anytime he got over 60 mph and turned the a/c on the temp would climb to 230 degrees. It was using a quart of oil every 500 miles Pulled it apart, took l out the chrome molly ring and went back with steel rings trying to dry up the oil usage. Still overheated. Finally put a thermometer in the radiator, showing @ 160 and the gauge at 210. It would not get hot enough to seat the rings. Put the old senor back on, temp got right and got the engine hot enough to seat the rings. no telling how many hours and money lost trying to figure out it was just a new bad sensor. I feel your pain.
I just wanted to say two things. 1) I'm sure I speak for others in saying thanks for all the hard work you do in making these excellent videos. 2) I hope you're making a very nice income from TH-cam for all this hard work!
I like the way you incorporate lunch into diagnostics. Nice work
We get value from all of your videos! Thanks.
I read through most of the comments and didn't see anyone suggest this, but being a heating/a/c guy, I would suggest that to be absolutely sure of the internal temp of the sensor, soak it in an insulated cup of crushed ice/water. This would put it at exactly 32 degrees and remove all doubt as to the actual temperature of the sensor.
Yes but he was trying to confirm it isn’t a wiring or pcm issue.
The change in resistance vs temperature is logarithmic for those thermistors. That chart you showed has enough data points to plot a log curve so you pick off interpolated values of resistance for any temperature. Also you could make a more versatile dummy thermistor test tool by putting a 100 ohm 10 turn pot in series with the one you already use. Allows for finer adjustment of resistance values. Might be useful for those picky GM drive cycles. By the way, the multi-turn pot I saw you using should be accurate enough so you don't have to confirm all the time with an ohmmeter (saves time).
You still need to check the resistance with a meter to get accurate results.
With a multi-turn pot you can set the potentiometric resistance ratio very accurately, typically 0.1% error, but when used in rheostat (variable resistance) mode the errors are greater due to the tolerance of the end-to-end resistance, typically 5%. Directly dialling the resistance value could have resulted in an error of up to 5.1%, which wouldn't have been sufficiently accurate for the testing that Eric O was doing.
I was yelling at Eric to dial in a temp on the chart then test the variable resistor.
Fantastic diagnostic approach to use the varistor meter. You'd have made a fantastic software developer! Thanks as always, Eric!!
I'm convinced Eric could have been a world class doctor or surgeon with his skillset.
Eric claims he is not an electronics guy...yet he has a brilliant understanding of how automotive circuits work.
I just get lucky once in a while Rich. I'm not an electronics guy, trust me.
As an engineer, Eric could definitely kill it in STEM if he wanted to. Critical thinking skills for days
@@SouthMainAutojust damn good 👍
I always learn something watching your videos. I was in IT for over 30 years, jack of all trades doing Cobol programming, newer languages, interfacing PCs and Mainframes, and PC repair. Your logical approach is the same as is used in repairing PCs OR in finding a bug in a program and I'm always impressed with your clarity of thought. Keep up the good work and I wish you continuing success!
I ran into a similar issue with my Holly sniper.
The temperature reading was off with the sensor that came with the unit.
I ended up purchasing a Delphi temperature sensor and that cured my problems.
Just to let you know, there are calculators on the web that will give you the exact ohms reading to temperature.
Great job and always great videos!
KC. How about a Link?
Seems about right. Cheap chinesium sucks and costs the customer more. Wish i had a mechanic like you here, woulda saved me tons of money. Thank you Mr. O!
One more reason to use OEM parts......less expensive in the 'long-run'. Delphi used to be owned by GM, so the Delphi parts should be 'compatible'. Another great diagnosis!
When troubleshooting customers RV appliances, the first question I would ask is "What is it doing or not doing?".
Always got a thoughtful concise and informative answer from the customer.
They are your best source of info and always know simple facts like "When I turn on the thermostat, nothing happens", even though they don't know the technology behind it.
Lots of good stuff here. My Subaru ej25 was running rich enough to wreck the cat. The coolant temp sensor was bad. The replacement stanpart was not calibrated ideally. Oem from a dealer solved it. Reducing part numbers by "retionalizing" their inventory could lead to unfortunate compromise being made by hasty penny counters. Their gain was my loss.
Another excellent diagnosis. It's unfortunate that the converters are junk. Hopefully the customer understands what happened,
The coolant temp diagnostics was spot on. A new GM sensor would have shown the difference. The vehicle sitting overnight proved that.
I found graphing the cat monitor and watching the digital readout will work. My wife 06 Sorento proved that when I was testing the cat monitor. That one was intermittently working then it would "track" the front B2S1 sensor, continually doing this cycle. Good call on the CTS, unfortunately 2 bad cats will ruin a good day.
Good one Mr. O!
In Philly 2000 an up can have 1 incomplete. You just have to get the evap to go befor the cat . Once the evap is ready it can have codes for the cat but the light can not be on . So a key cycle would turn off the light and try the cat test again . Just have to slip it through then .
Great diagnosis, but the biggest thing I learned is how thankful I am to live in a state that doesn’t do vehicle inspections.
Just moved to a state that eliminated vehicle safety inspections. At night it’s not uncommon to see 3 or 4 vehicles with faulty headlights or tail lights. Taking a walk thru a parking lot reveals numerous worn tires.
What we have here is a qualified experienced automotive mechanic dealing with the intrusive electronic components that want to monitor/dictate everything related to a poorly designed system.
Automotive engineers 👎
Parts designers👎
Old school mechanics 👍
And if you happen to get in to a collision, your car will rat on you big time.
Thanks Eric, you are helping me go through another crappy Canadian winter.
How I look to friends and family with a scanner in my hand: Wizard! How I feel with a scanner in my hand after watching an Eric O vid: a 2 year old holding vice grips
Great video Eric, Getting to know the drive cycle monitors takes some time. There is a lot to it. Good electronics diagnosis but checking the sensor characteristic. Hard to believe they actually make them wrong. I have actually designed temperature sensor gauges and had to characterize a thermistor. When at Cosworth they actually built the look up table with the actual sensor they were going to use thereby eliminating possible manufacturing errors.
Great comment. That must mean u r in jolly ole England. Am I right?
@@billrimmer5596 Not anymore, now in Springfield New Brunswick Canada. Miss old England but it is so difficult to live there unless you are very well off. Just help fix stuff here now mostly electronics and cars.
@@akdenyer I was born in Cornwall Ontario, but have lived in Los Angeles since 1955. I work at home on cars. It’s nice to meet u!!
Nice one Allister, fellow Brit here saying hi from over the pond
@@iuhjhfdskjsdf Hi there, yes miss England but no work and the EU drove me out.
that little potentiometer that comes in the AES wave connector kit is a go-to for me. I've had a number of situations like this one where new part doesn't solve the problem and I've been left scratching... further emphasizes that a known good, is good! Thanks as always Eric!
Another fine example of just because the parts is new, doesn't mean it's good!
The most successful advertising is providing knowledge, skills, and attributes when solving problems. Eric nails it without embarrassing people too much. He does make people wonder why dealerships don't do deep problem solving. I guess the answer is not enough ethical standards. It's one thing to throw parts at a problem to solve the problem, but throwing parts at a problem and still not solving the problem is criminal. Mistakes are normal but trust is the most important result.
A couple of years ago I bought a Standard MAF for my Ford when trying to diagnose a P171/174 lean error. I immediately got a sensor failure message upon installation and subsequent drive cycle . It went away when I put the original Motorcraft MAF back in.
I learned a valuable lesson that day. Even if the part is new, it can be crap. Thanks for reenforcing that message Eric - buy OE parts whenever possible folks!
I love watching all of the Silverado visits. I have a 2012 Chevrolet Silverado 1500.
If I didn't live in Alaska, and lived in New York. This guy would be my mechanic for sure
When I’m bored and want entertainment I watch other mechanics you tube videos, when I want education , I watch you videos. Not knocking other mechanics content but being a mechanic over 45 years but now retired I find I’ve been there done that. Some of the tougher jobs I catch myself saying stuff like , “ wish I had that tool or that looks easier from when I did that” . Your videos seem to be the jobs no one wants or gets in their shops.
I love watching you and your testing equipment go to work. Reminds me when dealer could not tell me why car would shut down after 10 minutes of running. Always happened to the wife never me until 1 Sunday morning. Waited 15 minutes cracked right up, got it home, got my Dodge engine book and voltmeter. It was an 84 Dodge caravan, 4 cyl.; there was a motherboard inside the distributor for lack of better name. When it got hot it would crack, when it cooled down it made contact. The dealer shouldn't have found it in 20 minutes, took me 4 hours and a bunch of fancy words directed to Dodge.
17:00 About how the PCM measures the Temperature: the Sensor line is connected internally to +5V through a Pull-Up resistor (typically something like 2kOhm). The sensor completes the circuit to ground, forming a potential divider. The PCM then senses the voltage at this connection, which is then translated to a temperature via a lookup table.
That clicking is a blend door actuator. The ones in my Impala make the same sound when going bad. It's turning all the way in one direction and trying to keep turning, jumping teeth on the gears inside the actuator
Well done Eric, I am surprised that the Standard brand is off, their parts are usually pretty fair. Just shows how much of a difference from part to part.
This is what happens when private equity companies buy out iconic brands. (Covers almost everything in the automotive aftermarket)
I actually spent the time to hunt down shelf worn NOS Blue Streak parts (Standard's 'premium' brand) when I did a recent tune-up
It’s unfortunate aftermarket stuff does not work better than it does. I chased my tail on my personal car for a lean code. 02 Sensor was replaced with Ntk on a Gm. Truck required oem Denso to fix it and turn the cel off👎.
Echlin and stranded motor parts used to be some of the better aftermarket brands but they have declined in quality over the last 20 years.
@@mph5896 I had the same problem when putting Bosch O2s in a Ram.
Great job Eric! Working for Chrysler from 1979-1994, every once in a while we would get some sensor out of wack for the old Lean burn system. Usually, it was caused by someone not understanding how everything works together so when somebody turns a screw the wrong way and leaves it things happen a downward spiral from there. I hated to get rebuilt computers as that was the norm then. To me, dealing with a lot of vehicles new and old, NAPA has quality problems on their Chinese parts! I always try to get factory parts if available.
Assuming OEM isn't Chijunk is a leap of faith in my view. They are going to conquer us 1 crappy part at a time.
Great video as usual. It would seem that in the race to become a go-to aftermarket supplier they are trying to cover all makes & models, but failing to get each variation of a part to be as good as the OEM. Your logical approach serves you well - keep up the excellent work!
I’ve also learned from experience, at least for GM’s. You will not complete a drive cycle, unless you use the key to start. I was using my remote to start and I couldn’t complete a drive cycle and somebody told me no try using the key after it sat for eight hours.
Nice diagnosis. Most shops would have seen a new CTS & looked elsewhere. I'm retired now but it is so enjoyable watching you diagnose & work on cars. Just had hip replacement surgery & I'll get back at it but on a limited basis for some of my older customers but now the priority is bass fishing & tournaments. Thanks again for enjoyable videos!
Hello Eric, possessor of Associates Degree in Electronics here to put in my 2¢. You had mentioned that you don't know how a PCM handels input data to calculate stuff and produce output to whatever it's sending the signal to.... BUT you wish you did. Experience tells me that the only people that know that stuff are the clowns that engineer it because it's proprierity information for a peoprierity system. Sure, there are techs and repair people that are curious enough to study it and find out what works, but It's not like you can take a class or something to find out.
That's a really good plan used to determine that BOTH temp sensors were bad parts. Unusual circumstance calls for a solid plan and you had it. You are a really good repair type person/ auto tech. I don't know what you charge your customers but they do get their moneys worth on these type of repairs. A combination of knowledge, skill and experience.... it's too bad that there aren't more guys like you in the repair business. THEN we would feel like we are spending money wisely.
Wow! You're thought process is so impressive! I love that you share that as well. It is sad that the places that manufacture items that are supposed to fix things make them unreliable, that dang BOB guy! Thanks again for what you are doing and tell Mrs. O. to keep you in line!
You have to respect the amount of testing he does confirm the issue, all the way through the process.
I love to watch your detective approach to solving these types of problems. You do a great job of diagnostics and sleuthing out the problem.
Mr Eric o these is a great video. This content was so difficult that
I was confused trying to figure what was going own. Until you explained the whole process. Thank you for teaching us. Again great content keep up the great work.
I’ll never forget the car you worked on where the power steering pressure switch was bad and making the computer say the evap was bad. You may be able to do it but I can’t and don’t want to.
As a NJ state emissions repair and inspection station l have run in to that very repair many times. Good diag as always,shame about the crappy after market sensors though. Some customers don't like hearing they have to spend more money to get the sticker though, especially for new cat's. "It's only a stupid light". How many times we've all heard that one! Thanks as always for great content Eric.
watching the O2 data showing it test the cats in real time was neat, reminds me of when I had a cat replaced on a buick to rid the 0420 code. few months later the light was back for the same thing. ended up watching the data while I gave er the beans and the rear sensor settled down. I just let it clear the light on it's own to be sure it was cleared.
Love these longer videos. Thanks Eric you made my day !😄 One more thing, so nice not to hear air tools and jack hammers in the backround !
I am glad there are people out there that understand this stuff so my vehicles can get fixed properly. But I wish there were more like you and my auto tech guy because there are just to many shops out there that should just doing oil changes
Always fun when you fix issues and now a full drive cycle runs and finds even more issues. Especially evap
My '97 F-150 would constantly go into limp mode. Ford dealership said it's a bad head gasket. Didn't believe it. I purchased a new sensor from them. They sold me the wrong one and it smoked the temp gauge. Temp gauge no longer worked, but it solved the problem, no more limp mode.
NAPA=not all parts active. It'll get ya everytime. wel done Mr O
The variable resistor is one of my favorite tools. I don't use mine much but when I need it, it's gold.
Fantastic. I was really wondering how a circuit could fail in such a way as to have "too little resistance"...ha !
Junky Napa parts drive me crazy. simple radiator and fuel caps last week. Nice find Eric, way to fallow through.
Good morning everyone! It's a great day when you can start it off with SMA!
The linearization circuit in the ECM for a NTC Automotive Thermistor has many different possible configurations. The most versatile is a VREF resistor voltage divider with the sensor on the low side (across the low side resistor). This provides good linearization adjustment and effective failure mode detection (sensor short or open). To diagnose the entire circuit you would have to know the ECM divider, VREF magnitude and the Thermistor resistance table (Resistance vs. Temperature). The ECM design team produce good results with the linearization circuit but the measurement errors (sensor sensitivity and ECM A to D resolution, usually the small VREF errors are not a factor if the measurement is ratio-metric) do increase as you move out to the temperature extremes.
From a legacy standpoint for GM the Intake Air Temperature and Engine Coolant Temperature NTC Thermistors are of the same basic type (thermistor pellet), meaning they have identical Resistance vs. Temperature tables, but the response is very different because of how they are packaged, the Air Intake has a plastic body (fast responding) and the Engine Coolant has a metal body (slow responding).
If the harness is good and the ECM VREF is good, then it has to be a problem with the sensor. In production you will find many different sensors (thermistor pellet) of the same type but with slightly different characteristic curves of around 5 Degrees C from one variant to another. If you put the wrong pellet into the sensor you are trying to make it will show a skewed value when used in the application, but other than the skewed reading it will look like it is working.
When working with an Automotive Thermistor supplier the characteristic temperature curves provided to the OEM (General Motors) are very accurate usually with a resolution of 1 degree C. If you have this detailed graph you can very easily verify that the sensor you have is producing the proper output at a given temperature, but unless you know exactly who makes the sensor it can be difficult to find on the web.
The OBD-II EVAP and CAT monitors usually require two drive cycles, and as stated in the video, meeting the drive cycle criteria is a challenge because the conditions to run the monitor test are very specific and complex. Also, if there is a failure it can take two drive cycles to register the errors via the Check Engine Light (MIL). If you have a scan tool you should see a pending OBD-II code related to the system in question before the MIL light is on. The HEGO Heater monitor usually requires two drive cycles to complete, even if you open the heater circuit, which we know the ECM is monitoring, the MIL light will not come on until two drive cycles are complete. Which to me is a little strange when the circuit is obviously open. I guess what I am trying to say is the monitor criteria is not always logical, but designed to meet the spirit of the OBD-II requirements as interpreted by the OEM.
"The computer is spon on, baby"
Well done Mr. "Danger" Powers.
Hey man u got a lot of respect from me for the monolog at the end about not working for free.
I've had great luck with delpi sensors, ignition coils and even their suspension stuff on my customers cars. They make some good stuff
Yep, you may pay more, but it is totally worth it.
I can tell you from past experience (and a box of "aftermarket" sensors) with my 98 Jeep TJ, that whenever you replace a sensor, make sure the replacement is OEM or a "known good" replacement. Just because it is in a new package, looks exactly the same, plugs in, and may seem to function as intended, does not guarantee the PCM will accept the data it relays. Chrysler products are notorious for rejecting aftermarket parts and mine is a 1998 (with a few monitors), so I would think that they only get worse as the number of finicky monitor parameters increase. And from what I see on your channel and others, finicky PCMs are not exclusive to Chrysler. Great vid, Eric!
your diagnostic, and knowledge skills are steller.
i repaired heavy equipment and cranes from 1972 to 1996 cat dealer and fed shipyard. the era of NO computers.
it was not important to know everything. but your succes depended on knowing where to get information.
now that need is 100 fold. and you just hit it out of the park consistantly.
kudos!!
I appreciate your instructive videos. I will also say that I have had similar problems with NAPA parts. I guess like everyone else, they are having problems with the suppliers.
If you monitor the coolant temp voltage pid you could just short the coolant temp sensor. If the voltage goes to 4.9-5 then from the connector back to the pcm should have good wiring. Aways a great diagnostic session with SMA. Very through Eric.
I like your videos it shows once again you are the man
Thanks for the operational principals explained. This troubleshooting the drive cycle will help us home mechanics.
5.3 + Trailblazer = Almost a hotrod. The SS trailblazer is for sure a hot rod. Great content.
I have a 5.3 Buick Rainier, Good power
5.3l just means crammed in there and harder to work on.😂
@@deansapp4635 Heck yeah, i would like to find a buick lacrosse super with the transversly mounted 5.3. Some what rare.
@@bryanphipps9131 That would be nice
Eric finally gets a V8 Trailblazer after all these years!! I have an 03 Envoy that also has the 5.3, but apparently 03 and maybe 04 used the older truck computers
Eric,
Outstanding video presentation.
Really appreciate how you break things down and insert the small bits of information that give the viewer a extremely clear understanding of the subject matter.
Thanks again,
great video Thanks for sharing love to watch your videos I have a GM Sonoma 91 4x4 has 4.3L I know it's old but I like fixing it had it for 6 months
This is the second time I🙃 have seen a mechanic with a new bad NAPA part.
Using a resistor box of some sort (potentiometer or decade box) to replace the thermistor is always a great way to find out if a system that uses a thermistor is properly representing the 'temp vs. resistance' value of the thermistor . The important thing is to know what the 'temp vs. resistance' value is supposed to be for the thermistor application because the computer is going to be scaled to a very specific range of resistance vs. temp.
As in this case the values of the sensors were wrong. Not sure if it was just the wrong part labeled as the right part, or a horrendous job of quality in manufacturing the parts.
Good video and provides food for thought. Could shave hours off the diag.
I love when both you and Wes post videos at the same time essentially
Very Nice and detailed diag. It is so frustrating when you are headed down the right path, but a bad new part throws you for a loop. Thanks again.
No substitute for proper service data and the experience on how to use that data. Great job, Eric.
Glad you were able to take us along for that one. You are legendary my guy
Years ago I ran into this working on a JetSki pulled two new fuel sending unit off the shelf both were bad pulled one out of a other customers key everything work like a champ
Thanks for the knowledge. Never would've looked there.
Would love to see many more videos on Drive cycle monitors. Your viewers in CA would watch every one! Those are the bane of our existence in our state!! Thanks for the informative Vids!!
big help for me Thanks Eric . my 06 chevy express 3500 has been giving wacky engine temps for a couple years. I replaced the sensor and still the same. You gave me a lot of great insight and info. I really like watching great diagnostics at work. You da man😉
At least it was showing fantastic oil pressure on the gauge during your test drive. As Derek on Vice Grip Garage might say, “that thing has ALL the oil pieces, perfect.” 😂
If you have at least 3 data points of temperature vs resistance (which you do in that chart) you can use Steinhart-Hart equation to calculate the resistance at any temperature, or vice-versa. You can build this in Excel if you want and have tables for all the common sensors, assuming they are NTC thermistors.
Volkswagen actually wants to contact you. They are also trying to figure out how to disable the drive cycles but only when they are being emission tested.
At standard atmospheric pressure you can make a thermometer calibrating water bath with ice cubes. If the ice is the majority of water, the water will remain at 32 F or zero C. until the ice is melted..similarly. all boiling water at standard atm. pressure is 212F or 100C
Yesterday I ordered a hub for an ‘01 Tahoe and AutoZone sent me the correct box but inside was a bearing for a Buick Century. Yes this is the BS we have to deal with on a daily basis…
It's good to know that I live in a region that doesn't require this kind of vehicle inspection. But on the other hand it could be a migraine if you never know your vehicle might have an issue like this. Being former military I know periodic inspections, while a pain in the woohoo, can often find an issue(s) before they become catastrophic. Where I live that is when you know you have an issue and the darn thing won't run or won't run very good.
As a fellow tech for over 20 years, ny first thought was a brand new sensor in the head and another brand new one from napa, both aftermarket and both reading incorrectly, was to get an oem one to test.
after market nock sensors do the same thing. Throwing codes new out of the box. Good Job!
Excellent video!! These are the best types of videos. Your very intelligent, and a Excellent mechanic/tech. Your costumers don't know how great they it,having you as their mechanic!!!
Great video. Now I have to go out and add a variable resister to my arsenal. That is just to cool for school when you can test the sensor like that.
The world needs more people with common sense like Eric O.
Eric O, I learned a very long time ago that brand new does not mean brand good, keep on keeping on!!!
Junk parts wasting everybody's time......great job figuring that out👍....still a learning experience
I had that same problem with my ford 12 or so years ago junk new napa sensors. got one from the ford dealer worked haha so from then on I dont use any aftermarket ones. crazy how picky the specs for calibration are another great video from you man cheers
Love this channel, no need for paper floor mats.