GM Truck REDUCED POWER P1515: EPIC BATTLE! -Part 2
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- čas přidán 7. 08. 2020
- 2 WEEKS after the initial diagnosis, the fussy Chevy set the dreaded P1515 DTC AGAIN!
I suspect the reman throttle body is the culprit.
Can we retrofit a brand-new later model 8.1L throttle body to this 2002 truck?
More and more hurdles come our way as I attempt to make the new TB work.
Enjoy the struggle!
Ivan - Auta a dopravní prostředky
I like seeing your honesty when facing a problem - sometimes 2 steps back. But continuing to try to solve.
We've all had those garage moments when you just want to close the hood and walk away.
Ivan, I can't wait to see video part 3.
I am so happy i do not own a FORD or GM anymore. I feel WAY less stress driving Toyota....never seen any of these problems. Ivan, i am rooting for you. You have never failed yet to repair a vehicle. I am amazed at your knowledge.
Thanks for the motivation Mike 👍😁
I agree completely, Ivan will prevail!!!!
This reminded me of the intro to the old ABC Wide World of Sports: "The thrill of victory and the agony of defeat."
Good luck Ivan. If nothing else, an epic case study.
I actually like these types of projects. Parts swapping different types of designs and testing to get them to work. And it's so satisfying when it works. Like putting a TPI on an engine that had TBI, with all the rewiring, burning chips, and moving hardware around. But that's mostly 80s technology. Nowadays it's all computer programming, and we dont get to see the sourcecode.
Thank you Ivan. Good job. Have a blessed and safe week to you and your family.
Wow, what a struggle. You're a champ for being so creative Ivan.
Wow-what a pisser!!! Good luck Ivan, I am certain you can clear this up!!
Thanks for showing the waveform for the throttle actuator.
I feel your pain Ivan SO close!!
Thats frustrating,thank u so much for posting this,u are way braver then I👍
Very nice video, thank you. It is a mystery.
Ivan.
I ran into the same issue a few years back on. 04 GMC sierra 8.1 liter. I replaced the TPS assembly or gas pedal. Problem went away for a few months. The assembly was from Autozone or Dorman crap. I replaced the assembly from Acdelco. Problem fixed.
If the assembly is from autozone or dorman . trash it. Then a few months ago. Problem resurfaced. Just as you were doing. I replaced pigtails. Cut one wire at a time and soldered the new pigtails. Then replaced the actuator. Bought a new kit. The throttle body is mechanical and is ok. Now the truck is running just fine. It appears the owner did cut wires. Anyhow. Check the gas pedal assembly. AC delco and Dorman will not communicate with each other. Hope that helps.
Waiting for part 3. Ivan this is a tough one when you have to travel so far. Like I said stick with scissor lifts. Bummer when you can’t get an OEM part. Maybe I should start collecting OEM parts for my two Hondas because I have no intentions of buying one of these new electronic nightmares.LOL Any how stay safe and well Artie 😒
I didn't like the look of those throttle motor pulses looking like "V" and not a true square wave on the bottom trace. It looks like the driver transistor circuit might have a current limiter on it and cannot pulse enough current to move the motor properly, or maybe the motor has friction or shorted windings. I think if you understand the strange scope patterns you will solve this one.
I was going to say ' put a resistor in the negative pot lead ' But that would correct one thing but create another.
You would need something like a variable gain d.c amplifier/attenuator, something like that.
I’ll say those reman throttle body might be dorman 😂
Especially if bought at autozone. Lol.
This reminds me of when I was a Porsche / Audi tech. Too many stupid electrical problems.
The spliced wires are suspect. I think the emissions would want the throttle to close a certain way maybe a delay in closing maybe that's messed up Is max throttle part of a governor system over rev system. I would have gotten two or three out of a junk yard getting the exact part. Great stuff. The replacement pedal might be suspect. I'd get a junk yard one or two.
One thing you could try is; rebuilding original Throttle body with new GM sensors; Rock auto site, has new part numbers. i think its; TPS -ACDELCO 213912 and IAC valve-ACDELCO 17113598. Not sure about that; Auto zone gas pedal setup too. Possibly you can rebuild the original on that, also. I agree; Tuff to troubleshoot, with bad reman parts. its like, Chasing your tale.
Wow, this is a tough one Ivan. When you fix it, your fix will be the probably be the one that keeps the 8.1's alive for few more years!
Maybe you only have to tell the throttle controller to re-learn the full travel of the throttle pedal.
Sounds like to me with a correctly working throttle body, the system has to re-learn the throttle and throttle positions?
I’ve seen Eric O. do this re-learn function. Give it a try.
And WHERE’S PART 3?? Jeez man, sitting on the edge of my seat!! Great video series!! Thank you. Now MOVE it!!
What trick will Ivan pull out of his hat for Part 3? Stay tuned to find out!
LOL I'm working on a 2004 that looks like the same truck! (well almost... this one looks like someone took a can opener to the doors....) Front and rear brakes, parasitic draw, rear bumper, front and rear lighting issues, etc. All I have left is to put the bumper on today....
Nice job explaining the process as always. Will a Relearn fix it??? Part 3!
There should be a relearn/calibration procedure. The way it resets itself may be an indication of this, IDK. I think owners who experience this have been able to shut off the engine, restart and problem temporarily clears as if it's not a solid failure.
Sorry Ivan, but it's s good to see a pro get as frustrated as I get on most projects.
If all else fails, buy an LM358 opamp and a few resistors. Set up opamp as a "subtractor". We won't use the 2nd throttle position sensor at all - it will be taken out of the circuit entirely. Wire the 5v wire of one of the position sensors (say, TPP1) to 2 places: 1) the opamp power input, Vin, and 2) to the opamp Signal 1 input. Then wire TPP1 output to the 2nd opamp (Signal 2) input. Then take the opamp output (which will be the difference of the 5v reference and the 1st position sensor output) and wire it to the 2nd position sensor pin going back to the TAC module. You will completely take the 2nd position sensor out of the picture, but you will always have the correct differential voltage that the TAC is expecting to see (the output of the 2 position sensors will always add up to the reference voltage). Problem solved. Biggest drawback is that you no longer have the "safety valve" that sets the "Reduced Engine Power" mode. If TPP1 goes back you are SOL. After wiring up & testing just mix up a bunch of epoxy, slather it around the LM358 and resistors, let it cure, install it and you are good to go.
Remember when there was a simple steel cable that went from your right foot to the throttle blades? I do...such simpler times!
What's not there cannot go wrong,
Manual throttle cables break as well just takes a lot more miles, the good old mechanical linkages require some maintenance but can last almost forever.
Todd Ector I throw a little graphite cable lube down each of the three cables that come off the throttle body of my Jeep once a year.
For those wondering why there’s three? Accelerator, TV (line pressure control for the transmission) and cruise control actuator. I’ve not had a failure of any of these since I started adding this to my yearly checks.
When the grounding-strap between engineblock and chassis went out, you'd have an additional path for the starter current too! Sometimes triple duty as an engine bay light/heater during cranking! 😉
Both of the Ford's at my house are over 15 years old and have throttle cables. They still work fine, even tho they are not as touchy as the electric throttles.
Said it before, the design of these engines have so many variables that it is miracle that they work at all. Rule of thumb, dont mess with engine design or any other design. The time factor is humongous and return on investment, is prohibitive. Best advice to give, is move on to the promised land and don't look back.
Excellent point about these fly by wire cars. I’m assuming they learned they can make more money if they sell you a new car/truck as opposed to just a new throttle body. Just like everything these days, ulterior motives are at play.
First, sorry for my bad English, it's not my native language.
I've worked on a few cars with DBW over the years, and if you clean or change the TB, you need to run a TBA (Throttle-Body-Alignment).
I would expect a Chevy Truck to require the same, due to the difference in a set of potmeters (difference in manufacture/different batches and so on).
Saw someone suggest to just start the vehicle and let it run for 25 mins or so and the TBA would be performed automatically. On VAG this procedure might seem to work, but running an adaption with a scantool is more precise and quicker than letting the car "guess" with fuzzylogics by itself. (And you won't get the FULL position just based on the LOW/IDLE position. It just sets a baseline.)
BTW, Thank you for your entertaining videos. I really miss working on cars when I'm watching you videos.
1. thanks for publishing videos on the weekend. After a long days work out in the Phoenix heat of 111f it's nice to crash on the couch with a beer and watch your videos!
2. Wouldn't it have been better to just buy a used throttle body for the same gen on eBay and save yourself some headache?
I'm looking forward to seeing the conclusion. If you can't make this happen nobody can!
That sucks, would it help if you could adjust the TPS wot at the pedal, resetting the wot just a little bit lower, great diagnosis and video, looking forward to how this concludes
Ivan, I admire your determination and perseverance. You keep fixating on the throttle body despite the fact that three different units exhibit the same problem. Perhaps the other potentiometer in the circuit is the problem? How about checking the pedal? Maybe he has a Dorman accelerator pedal position sensor?
At 3:11, you found the "desired TP" at 5. All of my cars never go that low. This would lead me to believe that you are getting an erroneous signal from the accelerator pedal position sensor.
BTW, I am really enjoying your channel. You are a natural born test engineer. GM needs to hire you to run their electronics test division.
I don't trust the reman tbs... Have to eliminate that variable, but that's easier said than done lol
@@vpimike2646 would that imply a vacuum leak somewhere, in the first video it set the code with engine not even running. I'm guessing maybe an EM interference issue causing the PCM to misinterpret one of the position sensors. Maybe something aftermarket, maybe a motorized thing like a fuel pump, something that kicks on at random times for a few seconds. It doesn't seem to be anything directly wired to the actuator module or throttle body, under the hood.
I'd also be interested in the signal (sensor) ground at the other end, or at a splice in the harness. If any of those three wires (sensor, 5v ref or sensor ground) is intermittent, the PCM is going to see insanity on the signal wire of a sensor.
I have had a lot of bad Dorman products over the years, try to avoid them since there all farmed out products from China with very little quality control. Cost a little less but costs you more in labor replacing it twice.or even more .
I had a similar issue with my 07 Yukon after cleaning the throttle body. I don't recall the exact code I had but I was having an issue where I would start the vehicle and if I gave it some gas it would stay and hold at a high rev 2-3k. Tried idle learn reset with no luck. Was on the verge of buying a new TPS but I tested the coils and the position sensor and ohm'd out fine.
I ended up having to reflash the PCM and the issue has been gone ever since. Very weird issue that the PCM must be storing some idle position values and may be a similar situation you are occuring.
The Amish don't have any problems with throttle bodies LOL cheers sandy
Just thinking out loud. It may be worth it to pull a Bernie T and use the oscilloscope to monitor both APP sensors, power and ground on the PCM, Throttle control module, both TPS and current ramp of the motor current simultaneously. I’d give weeks salary to see the correlation between all of these signals when it fails. It’s interesting that it failed when you suddenly release the pedal. Seems like CEMF at work upon releasing the pedal which switches the polarity abruptly on the motor. Thanks again for the video, the community is about to learn big time from your efforts!
good thing the customer has you to try a fix. Is it worth all the trouble and expense, only the customer can answer that question!
Had problem like this and it was just broken harness from engine vibration. It was inches from where you are working. If this is not problem, I think relearn too.
Robert
And one other remark: You will practically never find two redundant signals from any sensor to be at the same level of the sensed input, but there will always be a significant difference. Either going in opposition to each other (like here) or each using only part of the range (e.g. one goes 0.5..2V, the other 3..4.5V or so). The reason is for the ECU to be able to sense possible short circuit fault between these two signal wires (it should yield impossible signal combination). And the 0..0.5 and 4.5..5V are ranges where a fault is detected (with a real potentiometer it would correspond to some open or short circuit fault, these contactless electronic sensors set the voltage there when detecting some internal fault, to mimic a wiring defect so the ecu knows the sensor does not work).
One simple fix: Put a stop-screw on the APP, maxing out at 95%.
Although consider that the PID parameters are tuned for a less sensitive actuator, this means you'll have less control margins towards an instable system on that new style TB. Control instability shows as butterfly flutter/oscillations. It's probably OK, but check it for such tendencies.
Excellent suggestion :)
That is a great idea! I was thinking the same thing
+1 or the old brick under the gas pedal trick
If that was my car, no no!!!
You're reading my mind. Stop it. I am also thinking that the cause of the original issue may not be in the throttle body at all.
Makes you want to sing..."oh give me a carburetor and a couple good screwdrivers..."😃
2 × holly double pumpers.... But can you really justify a pair of those without a blower on such an engine?
Stupid big with a sprinkle of lunacy ftw!
Chased a similar problem for months on my mom's Saturn. Finally tracked it down to a weather tight connector in the DS foot panel (I think that's what it's called) I cleaned it out with electrical cleaner, used dielectric grease then a zip tie because from what I found researching here and on google was the connector would work loose, collect moisture and set codes resulting in RP mode. Hasn't done it since.
You may have already tried this Ivan, but even though the actual GM part is obsolete, ask a Chevy dealer if they can do a dealer search. Maybe somewhere in this country there may be one sitting on GM dealers part shelf, it's worth a shot if you have not tried that.
I had a Chrysler dealer do this for a 2013 Dodge Ram! Drivers door module discontinued apparently crazy how quick cars are outdated these days
Just to be clear no module was found at any dealer in the country. I had to pick one up from a junkyard !
You can also install an older intake and throttle assembly to drive by wire.
If there's no throttle relearn, the cool Ivan solution would be to wire up a circuit to translate the voltage range to what's expected and, in effect, tell the computer exactly what it expects to see 😁
Just put 650 holly and a throttle cable on it old skool😁🔧🔧
Parts cannon getting red hot at this point. I feel the pain. I have a 2003 2500hd and 2004 3500 that both have had the reduced engine power virus
Throttle cables break eventually as well, but they last much longer.
That being said modern vehicles and their precision controls to make them shift smoother, maximize fuel economy and minimizing emissions sadly require electronic throttle bodies.
Would Identifix or GM TSB's offer some help with the problem? Also support line at one of the remanufactured part companys.
Ivan you always pick the easy one's. Can't wait for part 3.
Curious what Identifazio is thinking about this one?
Just a question; should the throttlebody be relearned to the system? Did you check the cable loom there has been a lot of clipping and soudering in there. Anyway i remember some Audi's have to run at idle for about 25 minutes to relearn the throttlebody to the actuatorpedal and system.
That's something that I was wondering. The relearn system exists for exactly that kind of issue.
Interesting. I'll have to check on the relearn... Thought the parameters were preset in the TAC module
Newer GM vehicles allow you to relearn throttle positions or idle limits. Ones this old do not. I believe it was somewhere around 2007 - 2009 the relearn came into play
@@mikebrennan4534 I just looked it up, in case I'm dumb (happens more and more these days) and Cardone has a relearn procedure available for the part.
there has to be some sort of relearn procedure or it would be broken right from the start due to slight mechanical and TPS difference/offset.
likely the reason the old units with external TPS failed more often, wear in the gears/shaft/tps bore offsetting the control and TPS signals from known motor position and having slop in there would make it never right again.
from the looks of it, grounds to the TAC are very critical and known to cause random problems and the past repaired wire harness break issue. it looks like there may have been some programming updates also to help the issue.
the early setup looks like a chinese finger pull toy, no mater how you fight it's a lose-lose situation lol
Ivan -- I guess you've solved the problem by now in episode 3. But I'm curious whether the reduced span of the new TPS signal is due to the motion of the throttle rotation using a smaller proportion of the pot's range, or are there additional resistors in series with one or both ends of the pot? (Internal to the throttle body/TPS housing.) The latter is potentially fixable.
Reroute the wire harness of the throttle body away from the alternator !! The alternator will add and subtract voltage from the tps by the use of magnetic induction, during different vehicle power loads,
Or shield the wires with metal shield attached to negative ground.
Even a small voltage spike from alternator at the right time and , added to, or subtracted from, the sensor, will not agree within the tolerance of the computer.
@@sargetester99 do you mean like the original symptom?
I think a large problem with the alternator theory is when it us repeoduced with the engine off. It sound more like an intermittrnt ground issue to me. At least with the original aftermarket throttle body.
Master, is the engine off? May I ask if that makes any sense to you what you’re seeing?
Привет Ivan! I'm not sure about this one track, but if it has throttle control module it's need to be throttle calibration option... Try Launch
A good example of why I prefer my throttle to be linked via mechanical means. I never trust wires to control what was better controlled by mechanical connections.
Is there throttle body limits relearn or some kind of calibration? It seems like it needs one after replacing throttle bodies of TAC.
Honestly ivan i disconnect the battery anytime i swap a part like this. Usually 15 or 20 minutes. Time consuming but can help keep modules from acting funky after changing a part and giving you false information. @ 12:41
What about a throttle body relearn with the old tb and the control module? How many recalls or updates do they have for that old system? PCM or TAC reflash?
What about iATN? I know they've updated their system.
ReString all circuits involved from the TB to the throttle control module, I would also ReString the App. Circuits. At this point, I would seriously consider this. No Crimp and seals. I have access to terminals and build my own harness. GM references this issue in Document ID: 1869994
I have seen at least 6 simular cases in our Dealership. As Gm Technical Assitance explains it, Resistance in those connections can and will cause your issue. That why we build our own harness, Crimp the ends, add a small amount of solder to the terminal crimps, and eliminate the crimp and seals. Wire degradation and splice issues cause the issue. rarely a component failure.
After seeing all those spliced wires, and how sensitive this computer is to the voltage reading, I was thinking the same thing. Use good wire from one end to the other and reduce any voltage drops, especially at the lower voltages that this runs at.
What code did those cases set? If it wasn't the P1515 or P1516 then it's a different animal...
P1516 P2135. Mine was 2003 K2500 8.1 also.
PIndrag, PinFit issues, Fretting, And wiring splice issues.
had the same concern turned out to be the alt. it had bad diodes that were good bad good bad
One important warning here: What looks like a potentiometer, in a normal circuit even seem to behave like a potentiometer, in reality in most present cars is NOT A POTENTIOMETER, but an electronic contact less position sensor just designed to ACT LIKE a potentiometer in and ONLY in the original circuit (so only with the correct polarity and with the voltage within specified tolerance; otherwise it pretend an fault on the output). So swapping the power and ground will make it not working (but it should not be damaged by that).
Plus you may find the same OEM part number components each piece using different real position sensing method (but 100% interchangeable). It is common practice to use multiple suppliers for them, each then could be using completely different sensing method (real potentiometer could be, in theory, one of them, but most common are magnetic analog hall sensors measuring the orientation magnet on the rotor, or an inductive resolver measuring ratios between inductive couplings influenced by the position of a "flower" shaped metal rotor, but other methods exist and can be used as well)
If you had given him a 2 week guarantee it would have lasted a month...2hr drive is a heck of a costly service call.
i bet that the tac module has a issue mabee power or ground or programing or bad module because it a after market one ,because it can't handle the more curant load on full trottle ,thanks for the guest game for us
Or a bad soldier joint or processor
I saw Eric O. on a video doing the relearn trick on his scan tool. It took only one minute. Don't know the details, but I know he remarked that it was a nice feature of GM cars.
Don't think there is a relearn function on this truck...
A 15 minute ad seriously yes I watched the whole thing!!!
Wow lol that's as long as the video 😅
At the start part 3, do a 5 second beep with a picture of the throttle body while you get all your cussing and cursing out of the way. Then onward with a big smile.
Maybe try a search for 2002 chevy 8.1 throttle body Relearn procedure.
Unless you find the bottom cause of the problem, you will be chasing shadows trying to rectify this problem.
a) One unit is known defective, as it behaves erratic once its fitted.
b) The other unit is good, but suspective, as it may work for long and then suddenly out of the blue sets a fault code.
To get on with the problem, I highly recommand you dissect the known *BAD* one, and find the bottom cause of failure.
Dont spend anymore efforts into modifying the problem away. Thats exactly the route you used to warn against earlier in your YT channel career.
is there any kind of a Throttle travel calibration procedure ?
I was wondering if there was a learn procedure of some sort to calibrate the new motor and tps to the pedal assembly and controller.
Ivan, that is weird way to find out. I am thinking it's the wiring that is questionable. Causing skewed results. Retrace all wires and double check them. That's my guess
Did you check for any TSB's for this truck? For the throttle body assembly I would jump into a junkyard to get one
With Chevy's reputation concerning ignition switches is it possible that this may come into play? Thanks!
I'm working on a 2000 C5,p1120,p1220 and p1515. I don't have a scanner ,so using a dvm. New tps,new app sensor. Downloaded all data and following test procedures. It's tough.
Get a scanner it will make your life easier 😁👍
I'm wanting to see if this issue survives the throttle body relearn procedure.
Thanks. Is the relationship between vout hi to vout low to the span is 4 volt. So half throttle is 2 volt diff between wipers. Did you say if hi minus low is too great then abs value becomes too hi resulting in reduced power.??
Hey Ivan I had a similar issue with a Chevy truck . Customer had a dead throttle body , he got his own and installed it . All good for a few days then ....... he got a reduced engine power . He shut truck off restarted it and it was good . He kept having this happen over and over . He brought it to my shop and I cleared and did a throttle body relearn. That fixed his issue . That was 6 months ago all good . I was taught to always do a relearn when changing anything with the throttle body or gas pedal . Don’t know if you tried to reset and do a relearn procedure .....
Hey Joseph, What year was that Chevy?
HD diagnostics!
Have you ever burnt one down, you know to the ground.
Joken
I like how you leave out all the cussing and throwing of the parts.
I personally would ask the customer for the original pedal so the throttle body and and pedal can communicate with each other easier. A dorman and an AC delco don't work well with each other.
Ivan i have seem different issues on different cars..like ckp sensors..cmp sensors which indicate a performance issue..eventhough the vehicle has been on diifferent shops without any luck..what i do is replaced or use the original part...and run all new wires front the component in question all the way to the computer..reference voltage..ground and signal..it has work for me..especially on chrysler.dodge.jeep products..wires are not the best quality...
If its that pesky G105 junction I'm gonna be so annoyed, lol ok last time I use that joke. If you're not able to do a relearn, is it possible to add some resistors and get close enough to the proper range? Guess we shall see in episode 3. Thanks for the great videos.
Check SI to see if that truck requires a throttle position relearn when the throttle body is replaced.
Looks like the same throttle body that's on my 2005 6.0L. I know this because i just did knock sensors on mine!
I have in my mind that the owner changed the throttle pedal and put on a different one what i am gessing dorman , can that pedal mess it up?
Nightmare job and at 2 hours away.. maybe the later pedal unit would work as a paired system I guess it’s a lot more research or maybe a case of opening the old throttle body the one that chatters and sorting it yourself use the new motor from the new body as you have already purchased it and maybe check to see the potentiometers are clean
Good luck
We had a Mouse or Rat infestation on a Acura . And we had to repair the throttle body connector connections. And those Wires Were Shielded!! I'm assuming that they had interference problems at one point in time. I think it's not a bad idea to verify the repair that was done to those wires? All the best from Canada
EEPROM STUDDY GIVE IT A KISS
Some great ideas here, but I think it is Covid related
I see the frustration of the issues. What about a hot rod upgrade? Does Holley or someone make a good quality replacement with the correct wiring config?
No help at summit except Cardone remans...
I'm actually having the same problem on a 2003 avalanche and the throttle body has been replaced three times with AC Delco original parts the pedal sensors been replaced and the tac replaced and the pigtail for the tb. Im at a total loss
Bypass resistor on the tps to bump the voltage?
Is there some kind of throttle learn procedure?
Exactly what I was thinking. Throttle adaptation, need to be ran after any change or cleaning. Guess GM was depending on components to match exactly.
Still feel you have more underlying problems in the system, not only the replacement parts. Something not making a good connection all the time?
I take it the original obsolete AC Delco throttle body for an 02 Silverado LS 8.1L was p/n 217-1631? Obviously, you've repaired it, but there's probably a NOS floating out there somewhere. Last Amazon review was Feb 2019. (4) reviews, all 5 stars. Sounded like plug-n-play. So maybe no reprogramming needed.
Does the gas pedal have anything to do with the TB open/close positioning & sketchy signal ??
@MG Stevens well that's silly iven should know better than that you replace or test the pedal then the throttle body
Not likely the fix but if you needed to increase the span of the tps pot's output voltage you could use an "operational amplifier" or "op amp", usually two or more on one 5v ic, they have adjustable gain ( feedback ) and one could be used in an inverted configuration ( feedback to the inverted input ) and use a single t.p.s. pot on the T.B. to produce the opposing and equal outputs.
So the gain and span of each op amp can be individually adjusted with four trim-pots ( equalized or paired ) but you would need someone who knows what he is doing and done it before.
google "inverted op-amp"
And you could use the picoscope channel with independent ground to calibrate the setup or compare the T.B. outputs on the laptop screen so they would track identical graphs.
Is it possible that the actual root cause of the problem is an issue with the wiring harness? This is an electronic throttle system, so obviously the module has a very low tolerance for voltage errors. A little bit of resistance on those signal wires will wreak havoc on the system. A tenth of a volt is nothing in a regular circuit, but it won't be acceptable on this system. Resistance causes heat, so the longer the system is operated, the hotter the poor connection will get, leading to even higher resistance and Reduced Engine Power Mode. Of course, since there will be minimum current flow on signal circuits, it will take longer to heat the bad connection, and that makes the problem very intermittent at times. It may prove fruitful to isolate the wires from the module, sensors, and throttle body and do a continuity test with the good old incandescent test light. Stressing the bad wire with more current should reveal quickly where the issue is.
Root cause is the lack of a roots blower on this engine.
I think its time to take that old throttle body apart and see if theres any adjustment in there.
Sorry for My english. I think there is something trigering this, I mean why it takes 10 days to have the problem again? What the owner was doing? My Acadia used to have an error always under specific conditions and that helped me to solve the problem. I am the old school and have 1% of your knowledge and equipment but it works to solve problems also.
Damn you traveling 2 hrs? Thats an epic battle in itself! I hope you charging him good....?
He shouldn't Charge the Man anything.
2 hour drive to "Practice" Automotive work on someone's vehicle , then 2 hours drive again - 2 weeks later.
This Fella probably has one of the best personalities on planet Earth but I swear to God & Sonny Jesus, this guy has more Balls than a Brass A_ _ Monkey....One day he'll be doing Videos like "Chris Fix"
- ( Do excellent Automotive Work , but NEVER shows his FACE , is C.F. running from the FBI or some "Past" Customers )
Ex GM Dealer Driveability Problem Expert
Southern California ( L.A. County )
Those trucks I do believe they got a governor