Brand new Sierra - Codes P25A2 - U0101/100/146

Rocky Mountain At4 · July 10, 2020

On 7/6/2020 at 5:29 PM, jbr1888 said:

2019 Sierra SLT Crew Cab 1500 X31 6.2L with 13k miles. The truck has frequently made noises after I turn it off and inexplicably applied the parking brake. The noises sound like relays or servos clicking and humming. They're pretty loud. Then today I got in it drive home from work, and saw the CEL. I used my OBD2 device to read the codes and got Codes P25A2 - U0101/100/146.

My truck also makes a lot of the same clicking noises when I open a door or shut the engine off. I don't think that is anything to worry about. Annoying, Yes. My truck seems to engage the parking brake all the time by itself.

Sector7500 · August 3, 2020

I had the brake controller update done about 2 weeks ago and I make shre I use my parking brake all the time and these codes magically appeared again yesterday. Time for another visit to the dealer....probably with no solution. This has probably been the biggest piece of junk I have ever bought. Weekly visits.

Tazzin · August 16, 2020

Hey guys, so this post is to backup Datlon Delogu & jbr1888. I have a 2020 Siverado 1500 LT Double Cab. Got it in January 2020 after trading in my 2014 Silverado with 135K on it. (WHOLE NOTHER STORY THERE!). BUT I when I go this 2020 truck it was a 'loaner' special from the dealership. It had 3100 miles on it already. I now have about 15.4k miles.. (techically 12.1k miles that I have put on it). I was helping a friend move into his new house and pulling my 14' utility Lamar trailer with front axle brakes I put on after purchase. Also note that I have a Tekonsha P3 brake controller cause my truck was installed with OEM controller. I by no means come close to max'ing out the GVWR of that trailer/truck capacity. I think max weight I put on trailer was MAYBE 2500 to 3000lbs max. I don't think this has any relevance to the issue but stating the information just in case. Trailer is rated for 7000 lbs. SO, I made 2 trips without noticing any issues. But somewhere between the 3rd trip and going home, i notice the engine light came on. So when I got home I pulled out the Code Reader and I got a the 11 codes duplicated of course, but here is the order they read in first to last... U0146/P25A2/U0101/U0100/P25A2/U0146/U0101/U0100/U0146/U0101/U0100. I don't know the exact time(s) this truck 'threw-up' on itself but here are some things I did read about and notice that some of the information sort of matches what I have read:

1. I have all software updates, including a recent TCM being the latest - this was mentioned by others to have recent updates similar to TCM update.

2. I did backup the trailer to the garage to unload which was up a slight upgrade, my truck facing downhill. (i saw somewhere some information about steering wheel position sensor still being on after the truck is turned off and sensing some sort of vehicle movement while on a grade)

3. I did remote start my once or twice to get it cooling with trailer attached (it is currently HOT HOT HOT here in Texas). I never used the app to start it.

4. There was couple of times i did turn on the accessory power ( hitting start button without foot brake), then once done, I put foot brake, start the truck, then turned off to shut all power off. Don't know the timing of all these events as I wasn't paying that close attention but know I did do that while moving my friend.

I'm really hoping that this is merely a software issue. I don't believe I have had any other issues up to this point. BUT if this is going to turn into another gremlin issue. I WILL be done with GM trucks forever. To reference the "WHOLE NOTHER STORY THERE!" above, on my 2014 Silverado, there was a Neutral Safety Switch issue I kept running into AND a misfire on cylinder #5 that was starting to turn into deep engine issues and I have by no means abused my vehicles. You can see some of my information if you search for my name Tazzin or look this up 'P182E P0700 CODE'

I'm turning my truck in tomorrow, Monday August 17, to the small dealership that did the software update. I'll report back when I have more information from. I WILL be probing the tech to see if I can get anymore information about how common this issue is AFTER the recent updates.

Edited August 16, 2020 by Tazzin

bamorris2 · August 16, 2020

GM just came out with a new bulletin about this earlier this month, and then revised it this week. I was having the issue, so had the GMC dealership update the software yesterday. We'll see if it stops these codes from coming back.

Service Information

2019 GMC Truck Sierra 1500 (New Model) - 4WD | Sierra 1500 Service Manual 13131286 | Bulletins By Category | | Document ID: 5625003

#20-NA-155: Service Engine Soon Message at Start Up or Shortly after Start Up - (Aug 13, 2020)

Subject:

Service Engine Soon Message at Start Up or Shortly after Start Up

This bulletin replaces PIT5735C. Please discard all copies of PIT5735.

Brand:	Model:	Model Year:		VIN:		Engine:	Transmission:
Brand:	Model:	from	to	from	to	Engine:	Transmission:
Chevrolet	Silverado 1500 (New Model)	2019	2019	—	—	All	All
Chevrolet	Silverado 1500	2020	2020
GMC	Sierra 1500 (New Model)	2019	2019
GMC	Sierra 1500	2020	2020

Involved Region or Country	North America, Middle East, Chile, Paraguay, Thailand
Condition	Some customers may comment on a Service Engine Soon (SES) Malfunction Indicator Lamp (MIL) illuminated in the Driver Information Center (DIC) at start up or shortly after start-up. When checking for DTCs, the Engine Control Module (ECM) will set P25A2 indicating that the BSCM (Brake System Control Module) has set DTCs. The BSCM will have set any combination of multiples of the following communication DTCs. DTCs can be set current or in history. Technicians may find the following DTCs set: P25A2 U0422 U0420 U0151 U0159 U0146 U0140 U0132 U0131 U0114 U0102 U0101 U0100 U0074 U0073 U023A U026A
Cause	The cause of the condition may be due to a software anomaly. For these U-codes, the BSCM may detect vehicle motion after driver’s foot is released from the brake pedal and parking pawl engaged. If motion is detected within 5 seconds prior to stoppage of CAN communications, after engine shutdown, the BSCM will re-enable its CAN bus communications and search for messages from the CAN bus. When messages are not detected, the BSCM will set U-code DTCs and also cause the P25A2 from the ECM to set.
Correction	Reprogram the Brake System Control Module (BSCM) with the latest update.

Service Procedure

Caution: Before downloading the update files, be sure the computer is connected to the internet through a network cable (hardwired). DO NOT DOWNLOAD or install the files wirelessly. If there is an interruption during programming, programming failure or control module damage may occur.

Note: Carefully read and follow the instructions below.

Ensure the programming tool is equipped with the latest software and is securely connected to the data link connector. If there is an interruption during programming, programming failure or control module damage may occur.
Stable battery voltage is critical during programming. Any fluctuation, spiking, over voltage or loss of voltage will interrupt programming. Install a GM Authorized Programming Support Tool to maintain system voltage. Refer to www.gmdesolutions.com for further information. If not available, connect a fully charged 12V jumper or booster pack disconnected from the AC voltage supply. DO NOT connect a battery charger.
Turn OFF or disable systems that may put a load on the vehicles battery such as; interior lights, exterior lights (including daytime running lights), HVAC, radio, etc.
Clear DTCs after programming is complete. Clearing powertrain DTCs will set the Inspection/Maintenance (I/M) system status indicators to NO.

Click here for detailed picture of the image.

Important: TIS2WEB screen shown. Techline Connect screen is similar and will be included soon.

Important: If the Same Calibration/Software Warning is noted on the SPS screen, select OK and follow screen instructions. After a successful programming event, the WCC is located in the Service Programming System dialogue box of the SPS Summary screen. No further action is required. Refer to the Warranty Information section of this bulletin.

Reprogram the Brake System Control Module. Refer to K17 Electronic Brake Control Module: Programming and Setup in SI.

Important: TIS2WEB screen shown. Techline Connect screen is similar and will be included soon.

Important: To avoid warranty transaction rejections, you MUST record the warranty claim code provided on the SPS Warranty Claim Code (WCC) screen on the job card. Refer to callout 1 above for the location of the WCC on the SPS screen.
Record the SPS Warranty Claim Code on the job card for warranty transaction submission.

Warranty Information

For vehicles repaired under the Bumper-to-Bumper coverage (Canada Base Warranty coverage), use the following labor operation. Reference the Applicable Warranties section of Investigate Vehicle History (IVH) for coverage information.

Labor Operation	Description	Labor Time
2886978*	K160 Brake System Control Module Reprogramming with SPS	0.3 hr
This is a unique Labor Operation for Bulletin use only. Important:* *To avoid warranty transaction rejections, carefully read and follow the instructions below: The SPS Warranty Claim Code must be accurately entered in the “SPS Warranty Claim Code” field of the transaction. When more than one Warranty Claim Code is generated for a programming event, it is required to document all Warranty Claim Codes in the “Correction” field on the job card. Dealers must also enter one of the codes in the “SPS Warranty Claim Code” field of the transaction, otherwise the transaction will reject. It is best practice to enter the FINAL code provided by SPS.

Warranty Claim Code Information Retrieval

If the SPS Warranty Claim Code was not recorded on the Job Card, the code can be retrieved in the SPS system as follows:

Open TIS on the computer used to program the vehicle.
Select and start SPS.
Select Settings.
Select the Warranty Claim Code tab.

The VIN, Warranty Claim Code and Date/Time will be listed on a roster of recent programming events. If the code is retrievable, dealers should resubmit the transaction making sure to include the code in the SPS Warranty Claim Code field.

Version

2

Modified

Released August 05, 2020

Revised August 11, 2020 – Reworded vehicle models and updated labor operation

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

Edited August 16, 2020 by bamorris2

Parrish Mooneyham · August 19, 2020

Hey BAMORRIS.. that is EXCELLENT information.. I was almost certain the developer(s) screwed something up!!!!!!!! They need to be SLAPPED for that crap.. ;)...

I mean crap like needs to be THOROUGHLY tested in a few different models. Trucks with OEM BrakeCotroller, Trucks with aftermarket brake controller, Cars, SUVs etc... I mean come on, I'm SURE GM has a few spare vehicles around to test this out before putting into production!!!!!!!!! AND I bet if you put those developers in the vehicles they updating the software in, I BET you they'll do a better job because now if they screw up on it, THEY are the one being the crash dummy in the test.. hahahahaaha. Thanks again bamorris for the info.. that helps a TON!!!!!

Back in Black AT4 · August 20, 2020

Thanks a lot for the bulletin!

My new AT4 set these codes immediately after start-up while at a drive-in movie with my family moving around in the truck bed...the truck probably detected the movement while in park...it all makes sense now...

btw the check engine light went away after a few key cycles and the truck did not exhibit anything abnormal other than the indicator light. My dealer said not to bother coming in to clear the codes out of history.

Edited August 20, 2020 by Back in Black AT4

nateg20 · August 20, 2020

Thanks bamorris2 for sharing this new TSB.

I got these CEL codes a few weeks ago. At this time I read a TSB similar to bamorris2 's post (but not nearly as detailed) and interpreted it as if the TCM sees a wheel speed before it thinks it should (or after apparently too) it "disqualifies" that sensor, then the bus disqualifies the controller. Must re-qualify it pretty darn quickly though. I suspect this check is occurring when the systems are initializing (starting the engine). I realized I was slamming the truck into gear right after pushing the start button, especially if it was already warm. For about the past 2 weeks I've really tried to let the gauges sweep on every start before I put the truck into gear. So far, since then no CEL. My BT scanner read this CEL twice within a week.

But to prove or disprove my theory folks getting the codes, maybe try letting the gauges sweep during startup before putting it in gear and see if the codes go away. Maybe even set the park brake every time you turn it off too.

============1==============
U0101
Raw code: C101
ECU: 7ED
Status: Pending
OBDII: Data bus, transmission control module (TCM) - no communication
GMC: Lost Communication With Transmission Control Module Invalid Data
============2==============
U0100
Raw code: C100
ECU: 7ED
Status: Pending
OBDII: Data bus, engine control module (ECM) A - no communication
GMC: Lost Communication With Engine Control Module Invalid Data; Lost Communication With Engine Control Module Message Counter Incorrect; Lost Communication With Engine Control Module Bus Signal Checksum Error
============3==============
U0146
Raw code: C146
ECU: 7ED
Status: Pending
OBDII: Data bus, gateway A - no communication
============4==============
P25A2
Raw code: 25A2
ECU: Engine control unit
Status: Pending
============5==============
U0101
Raw code: C101
ECU: 7ED
Status: Confirmed
OBDII: Data bus, transmission control module (TCM) - no communication
GMC: Lost Communication With Transmission Control Module Invalid Data
============6==============
U0100
Raw code: C100
ECU: 7ED
Status: Confirmed
OBDII: Data bus, engine control module (ECM) A - no communication
GMC: Lost Communication With Engine Control Module Invalid Data; Lost Communication With Engine Control Module Message Counter Incorrect; Lost Communication With Engine Control Module Bus Signal Checksum Error
============7==============
U0146
Raw code: C146
ECU: 7ED
Status: Confirmed
OBDII: Data bus, gateway A - no communication
============8==============
P25A2
Raw code: 25A2
ECU: Engine control unit
Status: Confirmed

Parrish Mooneyham · August 20, 2020

Hey Bamorris... where did you go to get that information for that TSB? A GM website?

bamorris2 · August 20, 2020

Hey Bamorris... where did you go to get that information for that TSB? A GM website?

I paid the $20 and signed up for a 3-day subscription to the GM Service Info on the acdelcotds.com website. I was looking for R&R instructions for something else, but took a look at the recent TSB’s and saw this one.

Parrish Mooneyham · August 20, 2020

wow, never new that existed thanks for the info..

Parrish Mooneyham · August 20, 2020

1 minute ago, Parrish Mooneyham said:

wow, never new that existed thanks for the info.. Thanks for sharing that info on your dime...

gregus73 · August 21, 2020

I was getting the same errors on my 2020 Sierra.

The issue was random...and the check engine light would come on when the vehicle was left off for a few days.

Anyways, brought my truck into the dealer and they flashed firmware. Will see if the error returns or not.
Also...I printed out the bulletin for the dealer if this applies.

LongTrekker · August 22, 2020

708 miles on my new Single cab 4x4 5.3. love the damn truck but DAMN does it piss me off. no brakes and tons of codes after start up. Cleared and came back within 3 cycles. Appointment Monday AM. Code c05b0, p25a2, u0146

Mcropper514 · August 24, 2020

I had this error the first time last week with 40 miles on the truck. I have a decently inclined driveway and I was putting in car seats. Went for a drive with the kiddos and the light popped up. Called On-Star and they told me the codes which lead me to the forums and down the rabbit hole. I restarted the truck a couple times and it went away.. so I cancelled my dealer appointment for the upcoming Monday because I didn't have time to take it. Was installing my Retrax cover last week and it did it again. Seems to be if you mess with anything on an incline you are likely to get the light. Saw in this thread the post about a new software update, so took it in this morning. Everything was flashed up to the latest update. Will monitor it and let everyone know if I have any recurrences. Hoping this is the end of it.

KCU Beor · August 24, 2020

Mine threw the same codes at around 75 miles, but went off when I started the truck next. It happened a few other times intermittently, but hasn't returned. Maybe it was "fixed" over a wifi update...Lots of code written for these trucks.