U0101 / U0129 Codes and CEL

Elpresidente · February 23, 2020

On 2/17/2020 at 2:34 PM, splatmatt said:

Well it has been around 500 miles since EBCM firmware was applied and the dealer performed a history wipe.

One thing I noticed is MPG is about 1.5mpg better and the voltmeter on the dash is always riding above ~14.4V. After the update it now seems to behave more typical to the GM regulated voltage control system and zero codes including all of the modules.

What EBCM firmware update was applied?

does anyone have the bulletin number?

Edited February 23, 2020 by Elpresidente

splatmatt · February 24, 2020

On 2/23/2020 at 10:23 AM, Elpresidente said:

What EBCM firmware update was applied?

does anyone have the bulletin number?

This is a recall not a TSB: GM Recall #N192268091

https://static.nhtsa.gov/odi/rcl/2020/RCLRPT-20V055-2135.PDF

Check your VIN here: https://www.nhtsa.gov/recalls

Elpresidente · February 24, 2020

Went to the recall site. My VIN does not flag this recall.

as well after reading the bulletin. I do not have the ABS or ESC lights on, on the dash console. I know because the first time this happened took a picture of the dash console and looked at it now

have never used the app to start.

the last two times did not wait the five minutes to start the car.

not sure the recall applies to all the U code MIL errors.

if anyone else learns anything applicable. Please opt in. I know there are other people having this.

Elpresidente · February 24, 2020

As well the recall has documented it is for a 2019 truck. Mine is a 2020.

splatmatt · February 25, 2020

21 hours ago, Elpresidente said:

Went to the recall site. My VIN does not flag this recall.

as well after reading the bulletin. I do not have the ABS or ESC lights on, on the dash console. I know because the first time this happened took a picture of the dash console and looked at it now

have never used the app to start.

the last two times did not wait the five minutes to start the car.

not sure the recall applies to all the U code MIL errors.

if anyone else learns anything applicable. Please opt in. I know there are other people having this.

I never used the app to remote start either as I do not have a remote start.

I posted the recurring codes I was having earlier in this thread and you quoted me and asked what was the document that referenced my issue with these codes.

Have you scanned the codes yourself? You will need a code scanner that is capable of reading the modules. I use the BlueDriver scan tool https://www.bluedriver.com/products/bluedriver-scan-tool

Additionally, your best start is probably to follow chain of command at your dealership. If you have hit a dead end with the service advisor, talk to the service manger, and then call GM for additional support or try another dealership.

One thing I learned is if a module is updated, other modules may need to be updated as well so they can properly communicate with each other; otherwise and error may occur.

Also, find out how long your truck sat on the lot. If it sat for a long period of time and the battery was not maintained the main computer may need to be re-flashed and the a complete history wipe of the codes may need to be performed.

Elpresidente · February 25, 2020

Pulled the codes with two different readers, on different occasions. Was at home once and at Dads another time so used his reader another time.

Truck had only been on the lot for days.

Yesterday finally got the dealership after a couple visits to address; probably what happened is the internal engineer case approved the work. I know they changed multiple parts and reprogrammed.

when I pickup will update the outcome for the community.

splatmatt · February 28, 2020

My error codes are back again; no CEL though... dammit

whitesierraRT · March 21, 2020

On 2/10/2020 at 5:09 PM, splatmatt said:

I've been seeing these codes show up on my Bluedriver OBD II code reader even after today's most recent recall that refreshed the EBCM.

If anyone has a fix for this I would appreciate the info - dealer is clueless in the matter.

Here is the summary:

****Update

well, dealer said codes were history codes. Flashed ECM and reflashed EBCM for second time under latest recall. Performed a “complete history wipe” whatever that means - not sure how that is different from clearing codes. But I had to go back this morning for a B1517 as they left some connections loose.

Now I have driven 60 miles (since this morning) and 0 codes and transmission feels very smooth. Fingers crossed.

I'm having this exact same problem since purchase 4 weeks ago. Been back to dealer twice. I'll be back as soon as this virus thing settles down.

Kevin0311 · March 31, 2020

My 19 HC came up with these 4 codes talked about here today also. Check engine light went off after 2 restarts. Have had truck for over a year and 23k miles, recalls all been preformed.

just noticed window leak yesterday also

u0101

u0100

u0146

p25A2

Edited March 31, 2020 by Kevin0311

Elpresidente · April 6, 2020

Kevin0311 we have the same issue. Told everyone would come back and support. Have been in the dealership three times. First and last time they just cleared the codes. Second time they replaced the electronic brake module. As well they flashed it with the latest as of February software update.

during the second service they could not get the codes to go away. They did a software reset procedure multiple times and could not get the software to upload eventually they got lucky and got the upload to the EBCM to work. Although even by a brake bleed and physical reset they could not get the codes to go away so they just cleared them out of the computer.

Disappointed with the lack of fundamental knowledge the service writer and techs had about how to deal with a software issue. They think that a code a OBD2 code is a match for a solution . It’s a match for a system or component having a problem but it’s not a match for an excat matching root cause. They fundamentally did not grasp that different software problems could bring up the same obd2 code; They had no idea what a data debug or dump was that they could upload to the GM engineers.

Typical non logic or methodical troubleshooting; just random attempts at anything. If something clears a code or hides the code it that is good enough. Still a little baffled that GM tech training does not include what most junior high AP Computer students know about how to start troubleshooting software issues.

Supposedly over a month ago (about feb 20ish) a new software fix would be ready in a month and they would call me back. Have not heard back yet. Had the codes another time when my wife was driving the truck had her confirm as have been keeping my obd2 reader in the truck.

will put my service work order here and my GM case number.

Edited April 6, 2020 by Elpresidente

Elpresidente · April 6, 2020

Anyway we can get everyone to post their case numbers with GM/Chevy engineers. The techs at every dealership will have called into GM and made a case which has a number. If we all share the case numbers here. And share this thread with the dealership to give back to the engineers they can cross reference all the cases. If a fix is not in the works this will prove to the engineers and product team multiple people are having the issue and will get it prioritized.

blaster2015 · April 16, 2020

Just want to chime in. 20 Sierra AT4, 3.0, 500miles.

Just got P25A2, U0100, U0101, U0146, with a CEL. Going to go see the Chevy dealer tomorrow as the nearest GMC dealer is almost an hour away.

Has anyone truly gotten this cleared up? Any insight to encourage the techs to look in the right direction instead of just random guessing?

tbarn · April 16, 2020

What might that "right direction" be?

blaster2015 · April 16, 2020

2 hours ago, tbarn said:

What might that "right direction" be?

I suppose that's the real question, huh? Does anyone know what the "answer" is? Has anyone heard back from GM with a real solution?

Brizzo Jenkins · April 16, 2020

Add me to the club. I have a 2019 Silverado WT, double cab, 4x4. All recalls up to date. I warmed up the truck this morning since it was cold outside. After about 10 minutes, I got back in the truck to find the check engine light on. Hooked up the scanner and found codes U0146, U0100, U0101, and P25A2. I used the scanner to clear the codes, and the check engine light went away, and all codes cleared. So far they haven’t returned, but I’ve only driven the truck about 20 miles since then. Has anyone figured out what the dealer is doing to remedy this? Just curious, because I have that funny feeling that it’s going to come back and I’m going to end up at the dealership. And just FYI, I have never told anything with this truck before. I also had the brake module recall performed about a month ago. Never had any performance issues out of the truck. Truck ran fine, shifted fine, and break fine the entire time the MIL light was on

Edited April 16, 2020 by Brizzo Jenkins