The contact owns a 2022 GMC Sierra 1500. The contact stated that while driving at an undisclosed speed, the service brakes monitor warning light illuminated. The vehicle was taken to the dealer where it was diagnosed with failed rear brake pads. The contact was informed that the rear brake pads needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure but provided no assistance. The failure mileage was approximately 22,000.

- Davisburg, MI, USA

Master break cylinder went bad and leaked fluid in side cab on driver floor board. Dealer identified that master break cylinder needed to be replaced.

- Camden Wyoming, DE, USA

I was driving the vehicle with my 4 year old daughter and experienced a complete brake failure. The dealership responded by replacing the master cylinder (the truck only has 16000 miles on it). Upon receiving the truck back from the dealer, another brake failure occurred. This is a dangerous vehicle and GM has done nothing to make it right with me.

- Danville, CA, USA

The factory Installed Trailer Brake Controller - The brake controller disengages the trailer brakes after multiple applications of the brake pedal. If the ignition cycle is stopped and restarted brakes are then reconnected. The Truck is equipped with a Max Towing package and factory installed brake controller. Prior to disengaging the trailer brake, a message "Check Trailer Wiring" appears each time the brake pedal is applied, then after multiple brake applied, the message" Service Trailer Brakes" message appears and the trailer brakes are disable for the remainder of the ignition cycle. I had the brake controller serviced at a GMC dealership In Hillsboro, Oregon following the first failure of the system, they advised me that the problem was the trailer plug on my trailer and advised me of brand and model number to install on my trailer. After I installed this new plug problem remained. I then to the truck to the dealership where I purchased the truck in Salem, Oregon. After an inspection there I was informed that it was a wiring issue with my Canopy and that they had fixed it. Again the problem wasn't fixed and the brake controller continued not to work. On my next visit for the same problem I was advised that my trailer was the issue and that the truck wasn't the problem. So I took my trailer into a top tier trailer repair shop and everything on my trailer was functioning as designed with no repair required. These 3 visits were over a period of 14 months. Over this 14 month period I had two close calls while towing my boat and trailer. What I have now learned is that the factory installed brake Contoller is not compatible with my trailer electronic brake actuator, even though all of GM promotional information says that it is. In addition none of the GMC service representatives were aware of this problem. I had to point out an obscure bulletin to them. by GMC failure to advise owners of the problem many drivers are being put in harms way. GM needs to inform

- Hillsboro, OR, USA

I purchased this vehicle to tow a 7,600 pound RV trailer with Electromagnetic brakes. This truck has an integrated brake controller. The truck keeps giving error messages: Check trailer wiring issues. Brakes not connected, etc. I have troubleshoot the trailer wiring and replaced most of it. I still have the issue. Online I see many people stating similar issues. Supposedly my truck has an error code associated with the brakes but dealer is of not help.

- Morrisville, PA, USA

While towing my 7000lb car trailer, I get a message that the trailer brakes need service, then I get another message that the trailer brakes are disabled. At this point the brakes are shut off and no longer work. This is extremely dangerous. The problem is with the truck. It does the same thing with multiple trailers of tried with electric brakes. All of these trailers work fine by my other vehicle with electric brakes for the trailer.

- Somers, CT, USA

I bought the truck to pull a trailer and the truck is equipped with a max tow package. When pulling a trailer after a short distance a warning comes on a says the trailer brakes have been disengaged. I have had it to two GMC dealers and they refer me to a GM PIT5948A. C159C document and is says there is no fix. I bought the truck to tow and it is unsafe to do so.

- Helena, MT, USA

The contact owns a 2022 GMC Sierra 1500. The contact stated while pulling a trailer and driving 45 MPH, another vehicle entered his lane spontaneously, he depressed the brake pedal; however, the vehicle failed to stop. The contact stated that the -??trailer brakes disabled/service required-?? warning light was illuminated. The contact was able to quickly maneuver to the right to prevent an accident and continued depressing the brake pedal forcefully to stop the vehicle. The contact was able to continue driving to his residence. The contact took the vehicle to the local dealer but was unable to find a fix for the failure. The vehicle was not repaired. The contact stated that he continued to experience the failure. The contact took the vehicle to a second dealer: Scenic Chevrolet Buick GMC (2300 Rockford St, Mt Airy, NC 27030: (336) 429-5457) however, the mechanic was unable to find a repair for the failure. The vehicle was not repaired. The contact stated that he continued to experience the failure. The manufacturer had been informed of the failure. The failure mileage was approximately 1,200.

- Walnut Cove, NC, USA

When I initially started the vehicle, I noticed the parking assist would not turn on. No warning lights or messages were displayed so I didn't think much of it and continued on driving. Approximately 5 miles down the road while traveling around 45 mph, I came upon a stoplight with other cars waiting. I pressed the brake to start decelerating and the pedal went all the way to the floor and vehicle did not slow down/decelerate. The check engine light, ESC, trailer brake, and brakes warning lights/messages then illuminated. I was approaching the vehicle in front of me quickly so, to avoid a rear end collision, I swerved into the shoulder and was able to coast through a right turn and on to a side street where I eventually coasted to a stop. I narrowly missed a major collision and was fortunate that there was no cross traffic approaching when I turned on to the side street. This could have been catastrophic, especially if pedestrians had been in the area. After stopping, I restarted the truck and the brakes seemed to work, however, the warning lights remained illuminated. I drove slowly to the nearest dealership. They replaced the electronic brake control module. Truck has approximately 20,000 miles on it and is well maintained.

- Hempstead, TX, USA

The braking on this vehicle is dangerous! Very poor stopping power. I-??m am frightened to tow a trailer behind the vehicle because of its extremely poor stopping distance. This is so bad that I think there must be some sort of design error or something. Someone needs to look into this.

- Richfield, OH, USA

New vehicle purchase on 10/17/2022. Attempted to tow 7300 lb travel trailer on 10/21/2022. When tow began DIC warning message said -??TRAILER BRAKE DISENGAGED. SERVICE REQUIRED-?? Trailer is 2023 Airstream with no brake failure. Disabled trailer brakes not safe to operate. GMC Dealer acknowledged the failure but unable to fix.

- Hayes, VA, USA

After leaving my truck parked for a couple of hours over dinner I returned to find error messages stating "Service Power Steering / Drive With Care" and "Service ESC". I also received a notification from OnStar stating "Diagnostic Alert: Service the Antilock Braking System in your 2022 Sierra within 1 day." My power steering was non-functional, nor were any cruise control functions. Repeated stop / start cycles did not clear the errors or regain functionality. After parking overnight everything was functional, and the errors on the DIC were gone. Using a code scanner there were historical codes of U0131 and U0422.

- Sapulpa, OK, USA

Reference GMC PIT5948A : Service Trailer Brake Message with DTC C159C - October 6, 2022. When I connect my trailer that has trailer brakes the system recognizes my trailer and the trailer brakes work until I try to drive. I get an error message "Trailer Brakes Disabled Service Trailer Brake System". This may happen within a few feet or the longest is about a mile. GMC has no fix and the dealer while cooperative didn't/couldn't trouble shoot the problem as the above PIT has no known corrective action. Now I own a truck that has the "Max Trailer Package" that is rated to pull 13000 lbs but has no trailer brakes. I have eliminated my new trailer as the source of the problem by making a Trailer Brake Emulator, see PIT #5509H Diagnostic Tip. The error continues to happen. This puts myself and the public at risk if the trailer is heavily loaded.

- Las Cruces, NM, USA

The integrated trailer brake system errored and disabled during transport of a 5,000 pound trailer. There was a complete loss of trailer brakes. The problem has been reproduced by the dealer and the manufacturer informed. The warning was displayed at the time of the component failure.

- Morgantown , WV, USA

Vehicle is equipped with a max trailering package and includes an integrated brake controller. Trailer brakes become disabled within 1-2 brake applications. A "Check trailer brakes" warning is displayed on the DIC followed by a "Trailer Brakes Disabled" alert. GM has issued a Bulletin No. PIT5948. Currently there is no work around or fix for the problem.

- Peyton, CO, USA

The contact owns a 2022 GMC Sierra 1500. The contact stated that while driving approximately 70 MPH, the "Service Vehicle" warning light displayed. Additionally, while depressing the brake pedal, the brake pedal extended to the floor however, the vehicle failed to respond or decelerate. The contact stated that the ESC, trailer brake, and brakes warning lights then illuminated. After stopping the vehicle, the contact restarted the vehicle however, the warning lights remained illuminated. The vehicle was then towed to the local dealer who replaced the brake master cylinder and ABS module. The manufacturer was notified of the failure. The VIN was not available. The failure mileage was 9,700

- San Antonio, TX, USA

Truck drove as expected with no prior warnings. We pulled over for road snacks/drinks upon starting the truck we got a whole slew of warnings and warning lights. The warnings included:. Service ESC, Service Trailer Brake System, Service Brake Assist, Steering Assist is reduced Drive with care and finally Brake System Failure 43 MPH top speed. The check engine light, Traction Control Off and BRAKE light stayed on. We slowly drove to an O'Reilly's and got the ODB Code P25A2 (1 of 2 stored) and P25A2 (2 of 2 pending). I then noticed I had an email notification from OnStar Advanced Diagnostics: This is a Diagnostic Alert for your GMC Sierra. Dear [XXX], An issue with the Antilock Braking System in your 2022 GMC Sierra has been detected. Please service your vehicle within 7 days. The following morning the truck was was started and all seemed normal like nothing ever happened, no warning lights or warning messages Our of concern we dropped off at Garlyn Shelton Buick GMC service center to diagnose the issue. They reported finding code C05B0 for Brake Fluid Leak. Further states No external leaks found, Brake Fluid test passed 2 of 3 times, recommend needs Master Cylinder Assembly but No replacement parts available. INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).

- Las Cruces, NM, USA

service trailer brake system, service esc, steering assist is reduced, brake system failure. almost had an accident because of the brake system failure

- San Antonio, TX, USA