Network U0401 code and stabilitrak issues

[MrWilliams]

I have a 12 chevy camaro RS/LS V6 with 180,000 miles here's what I'm having an issue with. Now this doesnt happen everyday but its happens when I come to a full stop at times. The stabilitrak lights will come on and idle rough pulling a p0305. Diagnose the issue I have a scanner and I get a u0401 symptom 71 and a p0305 which is saying I have a misfire on cyl 5. Here's the diagnose and changes

Alternator and battery change
Compression test on each cyl 155 com.
Change injector #5 and full tune up
Change throttle body
Smoke test (cigar trick)
Polish all ground points on chassis and engine
All 02 sensors
Checked pcm and module harnesses
Fuel pressure is 48-52 has fuel pump and high pressure fuel pump
Made sure no wires next to exhaust
Check fuses and relays

I haven't check wires individually because there are too many wires to go through or my pcm could be going bad but sometimes it idles right....I've searched everywhere online and hardly anyone comes back with an answer or right direction....man I'm stumped cant tell if stabilitrak is causing the misfire or 2 separate issues

[gtstorey]

Probably at least 2 different problems. Stabiltrak light comes on pretty much any time it has another code and is likely a result of the other problems or is a separate problem. It's not the cause of the misfire. You will need to check live data when the misfire is happening to see if that leads you anywhere or you will likely need a very skilled diagnostic mechanic to take it beyond the steps you have already done.

For the U code, the below was pulled off a random website, but sounds correct. I can see if my 2010 service manual mirrors the advice below.

"Code U0401-71 indicates one or more modules onboard the vehicle has received invalid data from the ECM. It tells you there is an issue with either the charging system with low voltage affecting the communication or the harness to the ECM itself or the ECM itself is bad. This is what the dealer needs to check to diagnose and fix this properly. If the vehicle was in an accident or took on water this can affect it and give this code as well. They should also check with their scanner if there are any other body codes as well. Also make sure all grounds are secure or not damaged."

[MrWilliams]

Yeah most of the techs told me I've done what they would of done....but tear into the wire harness and believe me I would it's just work schedule is tight. At one point I did have voltage and amperage issues the multimeter indicated that so it was corrected by replacing bad battery and alternator.Then ohm the system which was good. I think in back of my mind the communication between modules drop for a moment as lost communication with pcm..like trans module and abs module communication because it tampers with braking and shifting gears.....I was just curious that anyone know something about chevy having known issues like program default or some side trick to the issues. Which I definitely wouldnt put pass me is my camaro was a gift back in 2019 it wasnt having these issues but then who knows what accident it might of had like u said I never bothered to check because i was in a tight spot in general but now i wanna check the history IF it's still on file somewhere ....my scanner is updated with the latest software.....the numbers are ok but I know theres an intermittent communication somewhere..I'll try to go through the harness when I take my vacay next month

[Mouse330]

U0401 is not a valid code for the 5th or 6th gen Camaros, V6 or V8, Look more into the P0305. Also if any tech or shop threw all those parts at a customers car without diagnosing the problem then they shouldn't be in the business.

[MrWilliams]

Originally Posted by Mouse330

U0401 is not a valid code for the 5th or 6th gen Camaros, V6 or V8, Look more into the P0305. Also if any tech or shop threw all those parts at a customers car without diagnosing the problem then they shouldn't be in the business.

The techs didnt tell me to throw all the parts in ...I did it because I already had problems with them before hand it just happen be one of the issues such as my throttle body, my battery and alternator were going bad per multimeter which cured the misfires at the time then the p0305 which prompted me to remove valve cover to make sure no valves were bent or spring damage I did not do a leak down test I made an oil cover so I can see valve movement. And my throttle body was messing with my air/fuel ratio and electric throttle pedal was change just for preventive maintenance but new news to me if U-code isnt a valid code which just helped me out ....thank u ...I also checked my ignition coil wires per multimeter...and that being said there other guys that had a similar issue with network communication but what fixed theirs they had voltage and amperage issues and til this day no further issues mines just happen to be more of an issue before I start taking big parts off

[Skelly]

Originally Posted by gtstorey

Probably at least 2 different problems. Stabiltrak light comes on pretty much any time it has another code and is likely a result of the other problems or is a separate problem. It's not the cause of the misfire. You will need to check live data when the misfire is happening to see if that leads you anywhere or you will likely need a very skilled diagnostic mechanic to take it beyond the steps you have already done.

For the U code, the below was pulled off a random website, but sounds correct. I can see if my 2010 service manual mirrors the advice below.

"Code U0401-71 indicates one or more modules onboard the vehicle has received invalid data from the ECM. It tells you there is an issue with either the charging system with low voltage affecting the communication or the harness to the ECM itself or the ECM itself is bad. This is what the dealer needs to check to diagnose and fix this properly. If the vehicle was in an accident or took on water this can affect it and give this code as well. They should also check with their scanner if there are any other body codes as well. Also make sure all grounds are secure or not damaged."

I am not going to re quote these symptoms again but....I have lived this before as many know here. A camaro with your mileage is best retired. But your tooo many symptoms are an indiication of ECM failure and I am sure others will argue the point but based on what you are reporting its factual.
Your ecm is different from 2010 -2011 but all have these codes upon failure.
The Vacuum purge valve is probably going to report your vacuum issues and no longer function correctly. Pull you over yet? Gas cap errors? Clear the codes with your meter and see if it will learn again and if it reports the Cat Converter not online after 125 miles you know what to do. Change the ecm but buy it through a reputable dealer. Your stabilitrack errors are artificial and upon changing the ecm they will all disappear. Cheapest route and the best diagnostic tool to help you eliminate the errors.

Sean

[MrWilliams]

Originally Posted by Skelly

I am not going to re quote these symptoms again but....I have lived this before as many know here. A camaro with your mileage is best retired. But your tooo many symptoms are an indiication of ECM failure and I am sure others will argue the point but based on what you are reporting its factual.
Your ecm is different from 2010 -2011 but all have these codes upon failure.
The Vacuum purge valve is probably going to report your vacuum issues and no longer function correctly. Pull you over yet? Gas cap errors? Clear the codes with your meter and see if it will learn again and if it reports the Cat Converter not online after 125 miles you know what to do. Change the ecm but buy it through a reputable dealer. Your stabilitrack errors are artificial and upon changing the ecm they will all disappear. Cheapest route and the best diagnostic tool to help you eliminate the errors.

Sean

The cats are reading and Purge valve was changed and made sure I hunted for vaccuum leaks per cigar smoke method checking intake thoroughly and other vaccum components but u did hit the nail on the head......in back of my mind my pcm may be the problem at the age and mileage of my vehicle I was trying to fix the little things before I condemn it......and I really dont want to get a pcm from the dealerships and some sites I'm not really trusting to order from unless someone had good reviews from a site but ...thank u...I like my v6 because my 76 oldsmobile 442 was my everyday car lol and u know if u have big block and an edelbrock carb a forth of ur check is going to gas so I'm trying to save my v6 lol

[gtstorey]

Way to early to condemn the ECM, but it's a possible problem. I have to admit I forgot to try and look up the U code in my service manual last night so I didn't see that the code wasn't valid. So at this point, all you have is a general misfire code which could be a lot of things.

What scanner are you using to get the false code. Some of the "gauges than have the code reader also that have been known to give false codes.

[gtstorey]

What manuals/books are you talking about?

[gtstorey]

https://www.camaro5.com/forums/forumdisplay.php?f=138

[gtstorey]

Originally Posted by Skelly

Appreciate the link and I previously Viewed these.Prior to asking Mr. Lee and its message base is years old and I was hoping to create a new forum. I did not want to run the risk of being punished here.

Thanks again

Sean

Not sure what you mean by starting a new forum. Start a new for sale post in the correct forum.

[Skelly]

Originally Posted by gtstorey

Not sure what you mean by starting a new forum. Start a new for sale post in the correct forum.

What I meant was to start a newer thread within the current forum. The books offered there are currently years old in price and can no longer be obtained.

I will go ahead and remove myself here as I do not wish a infraction here from this thread.

Sean

[gtstorey]

Originally Posted by Skelly

What I meant was to start a newer thread within the current forum. The books offered there are currently years old in price and can no longer be obtained.

I will go ahead and remove myself here as I do not wish a infraction here from this thread.

Sean

I'm still confused. You have something for sale. Post it in the correct classified section with what ever you want to sale them for. You can start the new post, doesn't need a moderator.

[MrWilliams]

Originally Posted by gtstorey

Way to early to condemn the ECM, but it's a possible problem. I have to admit I forgot to try and look up the U code in my service manual last night so I didn't see that the code wasn't valid. So at this point, all you have is a general misfire code which could be a lot of things.

What scanner are you using to get the false code. Some of the "gauges than have the code reader also that have been known to give false codes.

In the back of mind I dont wanna sound off on the pcm just yet....I ohm the system but maybe it could be just the harness itself on the network line. I've done every and anything except tear through that harness on the U code or could that code is masking another code......I searched high and low for close answers all i get is change coils and spark plugs but i haven't changed plug wires yet but if i change them will it solve or not solve the issue. I'm using the snapon solus edge just updated program not too long ago