5/5/25 woke up back seat entire truck flooring soaking wet back glass cracked. 4/8/25 transmission went out 117,000 miles 7/3/25 exhaust leak and placed nox 1. 7/8/25 127551 mileage exhaust leak replace gaskets, belt , tensioner, and pulley, 6/8/2025 3 knock sensors replaced and replaced intake manifold.

Source: NHTSA complaint ODI #11764362 · view all complaints for this vehicle at nhtsa.gov

- THE GROUND STRAP CORRODED AND BROKE APART. YES, I HAVE THE GROUND CABLE THAT FAILED, IF NEEDED FOR INSPECTION. - YES!!! THE TRUCK'S STEERING KEPT GOING IN AND OUT OF MANUAL STEERING AND THE ENGINE REDUCED IN SPEED ALLOWED, AND THEN THE ENGINE CUT OUT ON ME COMPLETELY - WHILE I WAS IN THE MIDDLE OF A BUSY ROAD TRYING TO TURN ONTO A SIDE STREET. THEN THE ENGINE WOULD NOT RESTART. - I HAD THE TRUCK TOWED ON A FLAT BED TO A GMC DEALERSHIP NEARBY. THEY CONFIRMED THE ISSUE WAS THAT THE GROUND STRAP FAILED. THEY REPLACED THE PART AT MY COST, WHICH FIXED THE ISSUES. - YES, THE DEALERSHIP INSPECTED AND CONFIRMED THE ISSUE WAS THE CORRODED AND BROKEN GROUND STRAP. - YES, THERE WERE MANY WARNING MESSAGES THAT STARTED TO APPEAR ABOUT 3-4 DAYS PRIOR TO THE COMPLETE FAILURE OF THE ELECTRICAL SYSTEM. I STARTED SEEING A MESSAGE ABOUT SERVICING THE TRAILER BRAKE SYSTEM, AND ANOTHER ABOUT SERVICING THE SIDE DETECTION SYSTEM. THEN A SERVICE POWER STEERING WARNING AND TO DRIVE WITH CARE. THE CHECK ENGINE LIGHT WAS OFF AND ON OVER THAT TIME. - I CHECKED THE WIRE CONNECTIONS IUNDER MY VEHICLE TO CHECK FOR BROKEN WIRES OR CORROSION. I DID NOT FIND ANY. I THEN CHECKED IF A HARD BATTERY RESET WOULD WORK, BUT IT DID NOT. LASTLY, I BOUGHT A NEW BATTERY TO REPLACE THE EXISTING ONE, EVEN THOUGH THE EXISTING BATTERY HAD NO ISSUES EVEN WHEN TESTED UNDER LOAD. THAT RESOLVED THE ISSUE FOR ABOUT 35 MINUTES THAT NIGHT AND THEN THE NEXT MORNING. AFTER THAT, THE ELECTRICAL SYSTEM FAILED AND THE TRUCK WOULD NOT START. AT THAT POINT I GOT TOWED IN TO THE GMC DEALERSHIP. I HAD TO LEAVE THE TRUCK FOR A WEEKEND, AND THE DEALERSHIP DID NOT COME UP WITH A LOANER, EVEN THOUGH I REQUESTED ONE. I GOT THE TRUCK BACK ON MONDAY AFTERNOON AND EVERYTHING WAS WORKING FINE SINCE THEN. - OVER THAT WEEKEND, I WAS AMAZED TO FIND OUT ABOUT THE BULLETIN GM RELEASED TO COVER ONLY SOME TRUCKS FOR THE ISSUE, BUT NOT OTHERS! MY TRUCK IS STILL NOT COVERED, DESPITE THE OBVIOUS SAFETY ISSUES I EXPERIENCED!!

Source: NHTSA complaint ODI #11742790 · view all complaints for this vehicle at nhtsa.gov

The brakes suddenly activate and cause the vehicle to rapidly stop with no warning of any kind and without any braking action being taken by the driver. Then, the brakes do not release and the vehicle cannot be moved as the brakes remain on. Turning the engine off and then restarting it or shifting to other gears does not release the brakes. The vehicle remains immobile and cannot be driven. After a few hours have passed, like overnight, the brakes release and the vehicle can started and driven just as if nothing had happened. A message briefly appears on the vehicle information screen each time this inadvertent braking occurs. It reads, “Brake Failure System”. These brake lockdowns occurred when driving on streets and in the driveway. No accident resulted but could have easily occurred. This is dangerous for a driver and occupants of a vehicle with this safety flaw as well as for other people and vehicles in the vicinity. This has happened five times. The last two instances resulted in the vehicle being loaded onto a tow truck and taken to a dealer of the vehicle’s manufacture. Thus far the dealership has not found what may be causing this intermittent braking problem.

Source: NHTSA complaint ODI #11719518 · view all complaints for this vehicle at nhtsa.gov

A known problem with these trucks is ground strap failure. I was driving and all the sudden lost power steering which almost caused an accident. There is a customer satisfaction program N252515590 that covers 2019-2024 trucks but mine was not included in this for some reason. I did have the truck fixed a my cost and was looking to get my money back from GM. I'm not sure if you can help with this but wanted to make a report that is happening with more trucks then they are fixing. If you need any other info from me please let me know

Source: NHTSA complaint ODI #11739135 · view all complaints for this vehicle at nhtsa.gov

The contact owns a 2020 GMC Sierra. The contact proceeded through the intersection when a vehicle crashed into the contact's driver's side door and wheel at unknown speeds. The contact stated that the other vehicle crashed into two vehicles, then crashed into the contact's vehicle and stopped. The contact stated that the police report stated that the vehicle that crashed into the contact was constantly moving at the posted limit of 50 MPH. The air bags did not deploy. The contact was treated for a left shoulder sprain and swollen right hand, however, it was unknown if other passengers sustained injuries. A police report was filed. The vehicle was towed to a body shop but the vehicle was not repaired. The failure mileage was approximately 34,800.

Source: NHTSA complaint ODI #11582161 · view all complaints for this vehicle at nhtsa.gov

I have a rear sliding window on the cab of my truck that leaks from both ends of the plastic guide. I noticed it when placing my young children in their car seats. I contacted my dealership and was informed the repair would cost $1500+ and not be covered by GM or warranty.

Source: NHTSA complaint ODI #11759726 · view all complaints for this vehicle at nhtsa.gov