GM Chevy Truck: "REDUCED ENGINE POWER" Case Study -Part 1
ฝัง
- เผยแพร่เมื่อ 23 ก.ค. 2015
- Join me on this twisted case study as I try to get this big-block Chevy truck back on its feet.
This '04 Silverado 3500 crawled to the shop with "REDUCED ENGINE POWER" on the dash, and DTCs P0101, P0113, P0120, P2135 stored.
In Part 1 I do mostly what I call "homework"...gathering information and making a game plan before troubleshooting an unfamiliar system. In fact, the preliminary research often takes longer than finding the problem on the vehicle! This may be boring to some, but is essential to a thorough diagnosis and expanding your knowledge. Remember, I am learning along with you!
Keep in mind, this is 100% Live and UNCUT! Not because I was lazy, but because this is real-world auto diagnostics. I felt it was important to record the thought process just as much as the scantool and scope tests.
I apologize in advance for the amateur camerawork. Hopefully the content will somewhat make up for this...promise to improve in the future.
I guarantee you will not be disappointed with the journey to the final fix, as it is not a common problem that you would find on a forum or Identifix :)
Enjoy and thanks for watching! - ยานยนต์และพาหนะ
![คุณอาเรียโต๊ะข้างๆ พูดรัสเซียหวานใส่ซะหัวใจจะวาย ตอนที่ 4 [ซับไทย] 【Ani-One Thailand】](http://i.ytimg.com/vi/_vK_cden2f8/mqdefault.jpg)
Love your logic assessments and attention to detail! Fantastic tools and you know how to use them effectively. (Coming from an ex HPE R&D engineer.) Thanks for sharing your troubleshooting process and use of debug tools. These tools are becoming more necessary with the technology that has been forced upon us.
You clearly had asked a lot of questions before you ever touched the vehicle, I can’t count how many times asking questions has helped me diagnose an issue.
Thank you for the great video!
I swear I'm not trolling you. You keep ending up in my feed. GM fly by wire system is a common problem issue. It's pulse width modulation so testing will be a problem for those without the "high tech" equipment. Check for reference voltage. If it's a intermittent issue it's likely a wiring problem. Check grounds related to TACM at ECM. Should be 6 black wires. There is a wiring harness that goes over the back of the engine that rubs on the components and shorts out. Fix that issue; you can ground the TACM to batt to confirm. If it is stuck in limp then the actuator is not calibrating. Check wiring connector at throttle body. Sometimes they split in the insulation. If wiring is good then change BOTH throttle body and TPS pedal. If you're hard up on money change pedal first then throttle body. There is no magic diagnosis with the fly by wire systems for the average folk. And btw Mr Pine? Did you remove the wire pin from that Kubota just to get a fault to pretend to diagnose so you can have a tractor repair video? My professional experience is screaming you did.
Awesome and informative video. You sent me shopping for the Power Probe ect2000. I need that after watching this video. I learned more about my truck than ever before. My 2003 Chevy Suburban has a lot of sensors. I love your logic and attention to detail! Thanks for sharing your troubleshooting process and the use of the tools.
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Great diagnostic tests with both parts 1&2. Have a 05 Sierra 5.3. Having very, very similar problems. Sending it to someone or somewhere to have it diagnosed. I hope their work is as good and worthy as yours!!
My problem was a wire from negative battery cable not being grounded properly......threw out code for crankshaft and camshaft sensors but was only a grounding problem :) thank God for honest mechanics
That's what mine is doing
Can you please tell me what it was? I replaced my battery cables and have had this problem ever since. Im wondering if i didnt ground it right but dont know where to look
I now totally understand why the Verus is so expensive! It has so much information built into the software and I just that multimeter scope! When you said about the ground wire I instantly understood that the potentiometer is acting as a voltage divider. Very cool! You are a lucky man to be working in such a beautiful area!
+Steven Watson Thanks Steven! Yes the Verus is a wonderful tool and information resource for sure. Finding a good used one will literally save you thousands over the brand new ones!
Good video Ivan. Had a problem with my wife's old Caravan. The lockout switch was stuck. Drove me nuts!!
It's really nice that the troubleshooter brings up the relevant PIDs.
wow! very detailed explanation! I watched the whole 42 minutes. I've had 4 GMT 800 trucks including a 06 Yukon and Sierra that I still own. Good to know this stuff. Thanks for taking the time.
Thanks for the detailed info. You actually helped me fix my reduced engine power issue. It ended up being the ground wire on the back of the engine. I bumped that wire while looking at something else and my brand new throttle body made a noise and the rep code came up. I need that snap on you have. Thanks again.
Thanks for your video Mine turned out to be my brake controller I unpluged it and I have not had a problem in 3 months before I found the problem I did the swap tronics thanks for your share
You did a great job troubleshooting and explaining the process! Watched both parts 1 and 2 and excellent job on finding the problem on a hard to find issue. TCM code you just got unlucky on that one....LOL Not your fault, probably could have reset it the first time after a second test drive and reseating the TCM connectors and avoided the embarrasment of the comeback but still, great job on a hard find. Goes to show that if you have the right tools, it does help! Hopefully you haven't seen this truck for a while or he came back with other issues for you to repair!!!! Thumbs Up!
I've been repairing cars and light trucks as an auto body tech for 42 years. In that time I have never thought that I'm done learning. Infact, if I don't learn something in a day...it was a bad day.
I have been rebuilding/restoring a 2003 suburban 1500 with a 5.3. I'm putting a new throttle body in it right now, as well as cleaning the intake, valve covers, and fuel rails while watching this video. Sure some parts are a little boring to sit through, (perfect for what I'm doing) but that's the real world.
If I were to make a video teaching what I do on a day to day basis, that would boring. Hours and hours of sanding, drilling spot welds, grinding. Just to show how to replace the rocker panels, inner rockers, and making or replacing body mounts.
I found this video very interesting. Most importantly I found this guy is the guy I would want doing my diagnosis work. That would be worth the money. Instead of an engine full of aftermarket parts that didn't fix any problems, but are probably going to create a few down the road.
This is exactly what my Tahoe does. When I bought it they had just replaced that TPS plug and crimped the wires instead of soldering them. It took about two months before I started getting the low power issue. I have figured out that it is at the crimping that causes the error but haven’t soldered them yet. I simply turn off the car and wait for a few seconds and then third it back on and everything is good again, for a while. Great vid and this gives me confidence that what I thought was the issue is correct.
Phillip Hale ii
Good stuff Ivan and hopefully it will be an easy fix with that ground wire. Looking forward to part 2.
P.s excellent informational video! Thank you!
Nice stuff Ivan. I have run into this before and it was the harness connection itself to the TB. I just have a useless autoenginuety so I just wiggled wires like you did and you hear the chime. The one I seen it was just a bad pin fit. Also when I seen almost 10.5 GPS on a hot 8.1 the maf is off or the throttle plate can't close , too much carbon . The IAT , I have never seen a broken ref wire, this is a first. That would through lots of substituted values for sure. The Verus is loaded with info, awesome. Look forward to the fixes. 👍
Steve Rob Hey Steve! Yes, pin fit issues are always a variable like you saw in the Silverado Airbag video. You can't imagine what I find in Part 2 though, where all the pieces of the puzzle come together. That's a good tip for the MAF reading; will be addressed in Part 2 as well. Stay tuned!
My last three Impalas did this and I finally figured out the problems coincided with my switching to E85. I filled with non-ethanol regular and the warnings disappeared and the check engine light even went out. Plus it said I was getting thirty nine miles per gallon which is almost 40 MPG ! ! !
This video showed up on my Home Screen. So I watched it. This vehicle reminds me of a different one, same make, different model. I’m not sure how they came to this answer but more then a few GMs had the same issue. The throttle body and its sensor was the issue. Quite a few had this same issue
great diagnosis video thanks
Damn you are good. Excellent troubleshooting!
A most excellent TPS report.
HAHAHA "yeahhhhh I'm going to go ahead and uhhh ask for you to get those reports to me ASAP....okay?" xD
Great videos on this truck. It is great to see that there are still great mechanics around. The "mechs" that are the norm are parts replacers or as you stated swaptronic, worst part they charge you for everything and fix nothing. Great job keep with it.
Very good video Ivan, your technique is really outstanding the way you approach the problem. Very educational. I worked on an 04 suburban a few years back with a similar issue and the only way I could solve it was to go to a wrecking yard and take the plug for the throttle body off another vehicle and solder it on the existing harness. I tried tightening the pins on the original but the issue kept coming back. Thanks for sharing your efforts.
George Heri Wow guess these trucks have pin fitment issues all over the place...makes for fun diagnostic jobs, especially the intermittent issues :)
I had the same problem with my 08 cobalt sport ! The throttle body actuator was bad and it was not letting the throttle body open to let enough air in !
Very good job 👍👍👍👍
Nice video 👌👌👌👌
You teaching very good
Nice work.
I need this guys brain lol, I toss parts at my shit until im right hahaa. Then i think to myself "oh well got new parts i was going to need down the road".
If an auto repair shop did what you do (just replace parts) you would run them into the ground and bad mouth them all over town and the internet.
You need to go and stand in the corner for a time-out parts changer until you learn lol
If someone would diagnose the problem then we wouldn’t have to throw parts at it I have the same problem and no one can figure it out
nice troubleshooting ivan
No downstream sensors because of the weight rating and whatever emission it was built with, didn’t have cat monitoring.
i see there was two issue ...A-T SENSOR which will make the engine run bad(-38)...2nd in diagnosing always remember what the teacher said in S.E.T CLASS...powers and grounds ,and having wiring schematics so you know what wires do what .(not all gm ideas were good--fly by wire ) nice video ,coming from a 30 yr GM tech
Good hunting. Grounds are just as important.
GMC ! Once you know what the gimmicks are to these motors it's no brainer !
Very good diagnosis procedure. Wish I could afford a Verus. I use a hand held scan tool, two channel oscilloscope and a multimeter for my electrical diagnostics. What camera are you using? I'm in the market for a good hd camera.
+Pet Rock's Garage Just a basic Sony HandyCam...pretty durable!
YES SIR My man Knows how To Teach You ROCK!!
Nice video I like your diagnostic approach I try to do it similar. I thought about getting a Verus but I couldn't find out if it could read all of the battery data for hybrids and EV. I have a DrewTech Cardaq-M its an OBD2 interface module that u can run any OEM diagnostic software through. Of course u need to pay for those subscriptions, but thats the only way i've seen to read all of the hybrid battery data. I'll have to read more about the Verus; have u ever used it on a hybrid?
Nice vid my friend! love that component test meter!
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I got that code before end up changing the oil pressure sensor and that fixed my problem
Intake air temperature sensor is very important in the fuel ratio, fuel ratio for hot air is different from the cold air, because density of the cold air is heavier than the one of the hot air.
my issue was from a bad connection harness on the throttle controller on the cowl behind the brake booster the accelerator pedal also hooks to it it drove me nuts it was interminent as ever usually after hitting a big pot hole in the road the only way i finnaly found it was grabing wires and moving them around and it seemed to happen more in colder weather !
My 2004 Chev Z71 is doing the same thing. It happened after I had a Tranny Swap. It is Intermittent, some days it doesn't happen at all other days it happens 15 times. I had a few shops look at it but no one has fixed it yet. Frustrating... she may make her way to the woods and just die there lol thanks for the video... very helpful.
Did you park it in the woods. I am considering the same thing. Please reply.
@@Deeznuts84356 Yeah, I smashed out the glass in all the windows and ran her until it died lol it still sits back there. I will never buy another Chevy after that truck.
Have a nice day Sir, I like your explanation for troubleshooting the car. I also experience same problem low power. But my scanner is not really good. I like your Scanner snap-on. But I hope you can help me to know the latest one of snap-on scanner now. And where can I buy that scanner? Thanks a lot Sir.
I had a factory original filter on my 2011 malibu with 59000 miles. I changed it yesterday but the air box was filled with sand.. it takes a long time for the car to accelerate... will cleaning the mass air flow sensor help??I vacuumed out the box n put a new air filter on...please advice thanks
I have the P0601, P0606 and U0107 in my 05 Buick LaCrosse 3.8L V6 after not driving it for about 6 months.
Very good video, more impressive is the patience you showed. it would be worth my time to bring my truck to you should I ever need to in the future. is that possible? I see you're in pa as I'm in nj. hope to see more helpful videos.
I'm having the same problem with a 2009 chevy 4.8 v8 and I replaced the whole throttle body with a new sensor , the app sensor, and the maf sensor, and it didn't fix the problem, I was wondering if I can check the voltages and grounds with a regular multimeter, and want to know more about the brake on the ground, thanks
It's almost always the throttle body sensor when it goes intermittent reduced power randomly during operation or on start up. I've replaced it on my 05 1500 silverado I rebuilt with my grandpa , My 03 sierra 2500hd with the 8.1L 496 big block just had the factory installed one go out and I've replaced the mirror component on a dodge as well. Sometimes you get screwy electrical shit but when it's an rpm issue you always look at the throttle body and components first
Moto, what camera are you using and video editing software?
I had to fix a wire once on the tb . it was broke about a 1/8 to 1/4 inch from the terminal in the connector . The Verus is nice , My ultra is broke right now but i will prob get another one . was looking at the modis ultra also . does having scope and scanner in one limit you anyhow . thinking of getting a vantage pro , .
wtbm123 Any scope is better than no scope! You can see how easy it is to jump between scope and scanner by using the "home" tab on the Verus. I imagine the Modis Ultra is very similar?
I have an 2008 H3 Hummer base model. I get p0651 code, Check engine light on and the rmp goes up and down. I want 15 minutes and the code goes away but the check engine light stays on. When it warms up the check engine light goes away and no codes. Please help me. I sure you have worked on hummers before. I replaced the battery, the battery connectors. The complete TB and I dont know what else to do.
Tb position sensor or pedal
ok.took.a minutyou passed the test.shebakka greetings.☺
My 05 Sierra had this type of issue. I replaced the throttle body. It had a bad TPS and on some models is not replaceable. I bought an ACDelco one on Amazon and it's been good for a few years so far. Plug and play. Unless you catch it slipping via an oscilloscope it's impossible to troubleshoot.
Hi ..
I have code p0106
Tahoe 2005 4×4 i swap ingen 5.3 to 6.2 litter i make tune for new map sensor and the code still come what can i do if u know plz
Was waiting for you to pull the plug and look at pins/ fitment??
It was my TPS sensor harness when i dealth with this same issue.
how much is diagnostic an how much time is associated with that be fore you charge more diag time
I had the same problem on my Sierra 2003 6.0 Sierra .and finally figured it out was the cable for the injector one was faulty check that out
Misfired most likely bank 1&7 because fuel injector 3 is shorted, so regapping/replacing spark plug and air filter will fix it!
Been watching your channel for a bit, saw the 2500 3 part series and saw you find the Russian restaurant, so I looked up your business and you don't look like an Ivan :)
haha what do Ivans look like?
@@PineHollowAutoDiagnostics Crew cuts and track suits? JK, i meant you looked like a steve or a scott
It is a bad PCM/ECU that causes the Reduced Engine Power. I had this problem and went to a Junk Salvage yard and pulled a used one off of a Chevy truck same like mine and it worked. The previous owner before me replaced 3 Throttle bodies and i myself replaced one from Autozone and yet the Code P1221 and R-E-P kept coming on.
Change out the PCM/ECU do the re-learn
10 Mins with key on crank
5 seconds off
10 Mins with key on crank
5 seconds off
10 Mins with key on crank
the Last 5 seconds off you turn the truck on. And no more Reduced Engine Power.
I can tell you guys how many nights i have spent pulling what little hair i have left out trying to fix this problem. Now i can pass this info on. I have a Video of my Truck on my Channel. Peace
Had this problem with my 2012 Malibu. Changed the air filter and it stopped. About a year ago or so
Phoenix MH83 reduce engine it’s cuase throadle body is dirty!! Bad fuel ratio, so yes changing fielder and plugs will fix it! Also people will Chang throdle body and find out later it’s light back!
I recently got a 2006 Chevy Suburban xl and when i got it the owner who was selling it to me said its has been running great no problems and I believed him 2 months later this bs started happening replaced the throttle body worked good for 3 days same thing happened again and I dont want to spend more money thats not gonna fix it can I get some help?
I have the reduced engine power in my Yukon Denali. Will usually pop up when it rains or I hit a puddle. My Modis keeps telling me of a 5 volt reference and the schematics lead to so many places but my traction control and stabilitrac always shut down. You ever heard of this in wet conditions? I haven’t yet.
Check for codes thrown and then check google for your Denali and try replacing the Throttle Position Sensor on the throttle body. If you have cleaned the throttle body while on the engine and moved the butterfly valve you may have broken the inside of the sensor.
I've been having reduced engine power on my 2002 gmc sierra 2500hd 8.1L and it all started when I accidentally broke the TPS changing the water pump. Well I replaced the TPS twice as well as the PPS and it's still saying reduce engine power. the codes it gave me was P1120 and P1518. Well now my code reader won't even connect and read the truck. I made sure it wasn't the code reader messing up and checked it on another truck and the code reader still works fine. Sometimes it will start and run just fine and you can turn it off and when you go to start it again it does it again. When you turn the key on the Throttle body will open and close rapidly. I've replaced every but the Throttle body it's self and the ecm. Any advice or tips would be appreciated!!
Did you ever find the fix?
friend could help me please. when it had the code p1271 the box did not change gear?
My brothers 03 silverado has had issues like this, where the engine would suddenly go into "reduced engine power". Just about every thing said it was the throttle detection module thingy. Basically I just reseated the connections for the throttle computing module and it hasnt come back yet. Its been almost a year now. It will probably come back now that i said something about it but its just a thing to keep in mind if you want to try to save some money.
Hey ivan, I have the following codes popping up on my Hummer H2 2006 - P1125, P2125, P2120 - reduced engine power and check engine light is on. I have changed the pedal Throttle position sensor as well as the throttle body but there is still no improvement. It revs to 2000 rpm sometimes but stays at 1500 rpm mostly. Really frustrated with this issue for the past 2 months.
btw there are no Hummer mechanics where I live, so I have to do this on my own.
really appreciate any help I can get.
+The average Guy Hmmm very similar scenario as the truck here, but with the accelerator pedal position sensor (instead of the TPS on the throttle body). Hopefully the TB wasn't too expensive, as there's no way that could be the fault! If it's a hard fault it should be easy to pinpoint with a few voltage checks at the APP. If it's intermittent like in my case, then I would scope the signals for glitches. Definitely suspect a wiring problem. Good luck!
Ugh, Dorman parts are utter junk. In ETCG's video where he replaced the timing chain on a Sentra SER, the Dorman valve cover he installed had a horrific design flaw, causing the camshaft lobe at the driver side of the engine to strike the underside, breaking off the baffle.
Dorman makes valve covers? wow.
Nice vireos
There's a yellow D with z lind through it on my dash whag is it?
I have a 09 chevy tahoe it runs great only code i have is evap. But it pops up reduced engine power some days not at all other days it can happen 2are 3 times i cut of the truck for a min are 2 then start it up and it is fine just need some help plz and thank u
you selected engine data at the main menu when tac data was an option. Would have given you all you pedal and throttle body tps 1,2,and 3 if you have 3.
Its usually the throttle body that makes it go into limp mode.
Is there a follow up to this video? We didn't get to find out if the Intake Air Temperature issue was somehow involved also. Remember that you were reading -38 Degrees F?
Yeah...Part 2!
I've got a 04 Tahoe with a P1516 that's driving me nuts!! Only happens when it's hot. Oddly, I can duplicate the issue with a hard brake sitting still, or turn the steering wheel all the way to the left or right. Only when hot, crazy!!! Grounds are good, tried new trottle module, and throttle body. I've replaced the pigtail to the TB as well. Any suggestions?
If you can recreate the problem, then I would hook up a scope or voltmeter to the relevant signal wires and watch for dropouts. It sounds like you have a wiring problem.
I'm having the same exact problem...did you ever figure it out.
Accelerator pedal position sensor is the p0220 thing that's coming up on a 03 cadillac escalade.
@@qwilliamson9117 I know exactly what it is..
Ohhh question format!? Do think this would call for change prior to the ground wire assortment fix? Have you ever cranked the vehicle and wiggled the wire for affect?
take a scanner pull codes record info delete and see what codes came back record that code that will be the main code the other code may of been set when pcm trying to adjust its way out of error but try that you cant lose nothing but corrupted data. if your a garage you need aldata or mitchels on demand
My 2003 Tahoe just had this pop up taking it to a mechanic tomorrow how expensive is it
Where are u locate do u work on other people’s vehicles?
i never understood electronic throttle, what was ever wrong with a good old reliable cable?
Nick Loss not so reliable? also, probably future proofing for the self driving car thingy?
Nick Loss they complained when the clutch was changed from linkage to cable and then to hydraulic all of which have their flaws and foibles.
Nick Loss a lot more wires involved a lot more sensors and parts that can go bad. which means a bigger payday to the dealers. yeah drive-by-wire is total fucking horseshit. I will never buy another fucking vehicle that doesn't have a throttle cable.
Nick Loss u are so right I vote cable in and that wire sh** out
LOL... makes a guy want to buy a good pair of shoes for walking... we can't get that any more either
it would make no sense for the TPS circuits to share a ground and power feed. that defeats the purpose of having redundant sensors. Power or ground is lost, then neither work.
My trailblazer 05 does not go up more than 20 or 30 speed.. Maybe transmission went.. ( bad)
Got my fixed it was the gas pedal harness
Any experience with a p1518?
It’s in the actual connector itself. I bet you everything. Or the separate ground.
I had this same problem with my 06 Impala. It ended up being my coil pack.
DJI OSMO
Love your vids!
I'm going back to dropping an old 350 and,getting rid all this shi t.
You have to have scan tool or tunner! Throws codes you go check it out and sometimes it simple fix ! I ordered a new throttle body for 88 with 10 year warranty . Put new speed censor , brake switch. 2008 running like a champ ! Great thing about GM on 2008 the parts are getting cheaper!
have you checked the wiring connection to the sensors on the carberautor?
Carburetor?
I like the reply's from people that have no idea. Carburetor on this?????
If you get this message and it smells like rotten eggs, your alternator is sending too much voltage to the battery. I had both checked at AutoZone and they said they were fine. I replaced them anyway, and my Yukon is driving great again.
hmmm rotten eggs? You mean battery is boiling? Yikes!
+motoYam82 That's right
oldsmobile bravada ?
How do I bypass my egr valvuepn a2003 gmc please help
I no longer trust Dorman sensors for this system. I've replaced the TPS and APP sensors. The TPS came with the wire harness kit. It kept throwing correlation codes. When I felt the wiper movement it felt rough in comparison to the OEM sensor. I've gone back to the OEM sensor without issues (yet). The correlation limit is relatively tight at 4% IIRC. The pedal position sensor is a "Standard Motor Products APS106 Accelerator Pedal Sensor". No codes for it since replacement.
You are awesome ! I am having a similar problem on my 2004 Yukon 5.3 - Sometimes the engine seems like its struggling or sucking fuel with no power then when I wiggle the wires connecting the MAF or the ground wire near the rear of the engine then the engine wants to run like wild horses. What do you think is the problem?
Ground wires
my plow truck is a 2003 silverado and right before this snow storm, throttle went away. Now it just idles high and no throttle. Looked at the plastic yes PLASTIC intake manifold and no cable there!
uh oh not a good time to break your plow truck! I was just plowing in our 99 Silverado...what a beast, even without tire chains! Good old throttle cable 4.8L V8
We have a 09 chevy cobalt 2.2, we have issues with our tps po2135, we took it to the chevy dealership they replaced the pcm tcm? and new throttle body and our car still goes into limp mode. We even bought another new throttle body and it still goes into reduce engine power mode....it will drive good till it gets hot then it would do that I don't really know if its heat or a short in the wire
+twoeagle86 You would need to drive it with a scope hooked up to the TPS sensors and catch the voltage dropout directly. Must be a connector or wiring issue if parts changing didn't help :)
I did a wire wiggle test by the tb, well car was in reduce engine mode and running, but what was weird is when I hooked up my engine code reader and erase the code well it was in limp mode the car started running good rite after I erased the CEL. The dealership put a brand new pcm their including a tcm....Im not sure if maybe the new pcm is defective or what. Its been parked for awhile but im bound to determine what might be wrong with it
I would very highly doubt that a pcm is defective, especially on a newer vehicle if everything else works fine. My suspicion is that you have a very intermittent wiring or connector pin problem. It only takes a momentary "glitch" or loss of contact to trip the code and go into limp mode. Once you clear the code the system is reset until the next glitch occurs, probably while driving from vibration. I would suggest do the wiggle test while the car is running fine (no CEL), and see if you can trip the code!
pp
Per the connector pin labels on your Snap on for the MAF/IAT, you have batt 12V coming in on one pin/wire for both sensors. The tan wire is the output for the IAT signal and you should not have voltage on it when unplugged, which is what you measured. Certainly you would not have a 5V reference signal on the tan wire for IAT output signal voltage to the PCM. You need to see what it reads when connected. If zero, and you have voltage going in, then the sensor is likely bad.
I was looking at this video to help a friend diagnose his mom's car with same problem on the TAC harness. I see in the second video you found a break in the tan wire, and of course when you plugged it into the MAF/IAT, the output temp signal voltage from the sensor can now get to the Ecu. That's not a 5V reference signal wire coming into the sensor, in other words.
Look up a wiring diagram :) IAT is not a 12V sensor. Just pulls down the 5V signal to ground through a thermistor.
Anyway, thanks for your reply. I tried a friend's Autel Elite today and it is a very good tool. His mom's car ended up being a bad ECM. We checked the TAC harness with a high impedence ohm meter from the ECM connector while moving the harness to see if resistance readings changed and it was all good, so programmed another ECM to the vin and it and the TAC errors did not return.
I want a Veerus..
New tps sensor top and bottom and new tac end of problem
👍