Chevrolet Silverado 3500 check engine light comes on

Filed Aug 17, 2026 · Transmission · AZ

VIN: [XXX] Make/Model/Year: 2020 Chevrolet Silverado 3500HD, Duramax L5P, Allison 10L1000 Recall: N242454440 / N242454441 (the federal safety agency 24V797) Description: Vehicle had N242454440 completed May 2026 (TCM software update for harsh shift / wheel lockup). On XXX at 103k miles, vehicle exhibited same defect: harsh downshift 8th-9th gear, CEL on. Diagnosed as TCM failure per N242454441. Vehicle at O'Reilly Chevrolet Tucson since XXX (18 days out of service as of XXX). Dealer states TCM on national backorder, SPAC ticket opened, no ETA. Dealer denied courtesy transportation stating out of warranty at 103k, despite recall being federal safety recall with 15yr/150k special coverage. This is failure of remedy for safety recall that can cause momentary rear wheel lockup. No parts available, no transportation provided. What I want: GM to provide rental coverage and expedite TCM repair per recall obligations. Owner: [XXX], [XXX], [XXX], [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Feb 20, 2026 · Fuel system · NY

Service engine light kept coming on the dash, and the code came back to a faulty DEF heater. My truck had a reduced power countdown on the dash indicating the truck was going go to into limp mode after x amount of miles. On warmer days the code would go away and there would be no reduced power. The vehicle was diagnosed at a GM dealership and confirmed the DEF heater was bad, but was notified that there is a bulletin with GM for this issue occurring in many other diesel trucks. My safety was put at risk due to the rapidly changing reduced speed milage, at any point it could drop from 100miles, to 10 miles until reduced speed. This could cause an instant car accident while driving if the truck were to randomly slow down to a speed much slower than the speed limit. IE- driving on the north way (65 speed limit) and having the speed drop to 5mph unexpectedly when you just had over 100 miles to reduced speed.

Filed Feb 8, 2026 · Electrical, Fuel system · OH

My 2021 chevy 3500hd diesel had the engine light come on and the service emissions system popped up in the info screen. It said in so many miles speed would be limited. I took it to the dealer and they said the def tank would need replaced because the tank wiring connector overheated and would cost me over $2k.

Filed Oct 18, 2025 · Brakes, Engine · TX

I was driving down the highway at speed limit when the dash lights came on and the truck started jerking went to a mechanic and he stated it was a fuel ejector after getting it replaced the issue still occurs often check engine light comes on and off and this the only transportation I have for work

Filed Oct 6, 2025 · Transmission · 146,000 miles · GA

The contact owns a 2021 Chevrolet Silverado 3500. The contact stated that while driving approximately 65 MPH, the vehicle unexpectedly went into Low Power Mode, with the check engine and low power mode warning lights illuminated. The contact was able to restart the vehicle. The vehicle was taken to an independent mechanic, where DTC: P2706 and P2732 were retrieved, and the contact was informed that the valve body and certain components of the transmission required reprogramming. The vehicle was not repaired. The contact later received notification of the federal safety agency Campaign Number: 24V797000 (Power Train). The dealer was contacted but the vehicle was not diagnosed or repaired by the dealer. The manufacturer was not made aware of the failure. The approximate failure mileage was 146,000.

Filed Oct 1, 2025 · Transmission · CO

I was driving on the interstate at around 65mph. Towing my fifth wheel. Transmission started shifting hard with a loud bang that sounded like we hit a huge pothole. A message popped up in the screen indicating “Reduced acceleration, drive with caution”. The transmission seems to be stuck in gear as we exited the highway. Check engine light was on. Came to a stop at a stop sign and barely had enough power to pull into a parking lot. We had the truck towed to a nearby dealership. Fault codes P0700 and P0747 were present. Service advisor said valve body would have to be rebuilt. It’s been 2 weeks and the valve body cover plate is still “backordered” with no estimated in stock date.

Filed Aug 10, 2025 · Transmission · WA

Driving on highway at 40mph while towing a trailer the rear tires briefly locked up, then the Check Engine Light came on and vehicle went into limp mode. Dealer confirmed transmission valve body issue. Same problem as recalled on earlier model year vehicles. Seems like 2023-2025 vehicles should be added to the original recall to ensure support and long-term warranty protection.

Filed Jul 10, 2025 · Engine, Transmission · 28,000 miles · FL

The contact owns a 2020 Chevrolet Silverado 3500. The contact stated that the check engine warning light was illuminated. Additionally, the vehicle later failed to start and became undrivable. The dealer was notified of the failure and an appointment was scheduled for diagnostic testing and for the manufacturer internal recall repairs. The vehicle was not diagnosed or repaired. Additionally, the contact became aware that the VIN was included in the federal safety agency Campaign Number: 24V797000 (Power Train); however, the local dealer was contacted and informed the contact that the dealer was not aware of the recall. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue via email, but no assistance was provided. The failure mileage was approximately 28,000. Parts distribution disconnect.

Filed Jul 8, 2025 · Transmission · KY

The contact owns a 2020 Chevrolet Silverado 3500. The contact stated while driving 65 MPH, the rear wheels locked-up. The contact was able to pull over to the side of the road. The contact resumed driving, but the vehicle was driving roughly, and the failure recurred while driving 30 MPH. The check engine warning light, the electronic stability control warning light, and other unknown warning lights were illuminated intermittently. The contact pulled into a gas station, where a mechanic inspected the vehicle, but the cause of the failure could not be determined. The vehicle was towed to the dealer, where it was diagnosed with transmission failure. The contact was informed that the transmission needed to be replaced. The vehicle was not repaired due to the cost. The contact related the failure to the federal safety agency Campaign Number: 24V797000 (Power Train); however, the VIN was not included in the recall. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was unknown.

Filed Jun 2, 2025 · Transmission · AL

Transmission shifting hard while pulling lawn trailer. Truck goes into limp mode, exhaust brake shuts off, and check engine light comes on P0747. Dealer said bad valve body which could have damaged transmission. No parts in sight. Known GM issue bot my 2023 3500HD is not covered in recall????