2020 GMC Sierra 1500: check engine light

Filed Oct 23, 2026 · Engine, Steering · MN

This morning it seems as if my 6.2L GM motor threw a rod. All the initial sounds and check engine information point toward that. I will be taking it to a dealer to confirm the issue. Data center driving ability and sounds indicate steering was affected as well or is somehow connected.

Filed Sep 24, 2026 · Engine · CA

While slowly accelerating from a stop, with 4 family members in the truck, the engine began to run rough for about 1-2 seconds then multiple notifications flashed across the dashboard (Check Engine, Steering Assist is Reduced-Drive with Care, Service ESC, and Service Parking Brake). The road we were on was steep and twisty and did not have room to pull over which put us in an unsafe position with compromised steering and no shoulder. We made it 2 miles home but there was smoke coming from the exhaust and the engine ran very rough. Truck was towed to my mechanic. Mechanic confirmed issue. Diagnosis was misfire in #5 cylinder, confirmed initial compression upon startup (1 second) then compression loss and cylinder full of oil due to failed lifter. No previous issues prior to failure.

Filed Sep 14, 2026 · Engine · 115,000 miles · MN

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving approximately 55 MPH, the vehicle started losing power and decelerated. The check engine warning light was flashing with several unknown messages displayed. The vehicle was parked on the side of the road and later towed to the local dealer to be diagnosed. The contact was informed that the lifters, push rods, and camshaft had failed and needed to be replaced. The lifters, push rods, and camshaft were replaced, and the vehicle was repaired. The contact stated that approximately 6,900 miles later, the failure reoccurred. The vehicle was towed back to the local dealer, and the contact was informed that the engine crankshaft and connecting rods had failed and the engine needed to be replaced. The vehicle was not yet repaired. The failure mileage was 115,000.

Filed Aug 24, 2026 · Engine · FL

I purchased my 2020 GMC Sierra 1500 AT4 with the L87 6.2L V8 new from a GMC dealer in March 2020 for $65,910 (VIN [XXX]). The truck has primarily highway mileage, very little towing, and has been well maintained. At 166,634 miles on [XXX], the truck developed a flashing check-engine light. The GMC dealer diagnosed “Cyl 3 lifter failure with camshaft damage” and determined that replacing the engine was preferable to repairing it because of the vehicle's mileage. The dealer installed a replacement OEM GMC engine and replaced both broken engine mounts. The replacement engine and installation cost $11,778. The replacement engine has subsequently required multiple repairs. At approximately 170,411 miles, the GMC dealer documented an exhaust leak that had occurred since the engine repair and a coolant leak from the upper radiator hose; both were repaired. At approximately 187,699 miles, the truck experienced overheating, coolant leakage, and loud engine-area noise. The dealer found that the water pump was coming apart and replaced the water pump and related components. I am reporting this vehicle because it is a 2020 Sierra equipped with the L87 6.2L engine and experienced catastrophic lifter/camshaft failure requiring complete engine replacement, followed by multiple engine-related repairs. I believe this history is relevant to the federal safety agency's investigation of L87 engine failures in earlier model years and warrants consideration when evaluating whether the known L87 engine defect extends beyond the vehicles currently covered by the recall. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 24, 2026 · Engine, Transmission · GA

The 5.3L Engine active fuel management failure problem. This known problem with the GMC motors was not disclosed by any dealerships or the manufacturer. While driving down the roadway, the truck had an engine malfunction and I was fortunate enough to be able to safely pull over. The check engine light activated and I took it to the dealer the next day. I was informed by the dealer that this was a known, common issue that GM was aware of but was not offering assistance. I had to pay $11,000 out-of-pocket because of this.

Filed Aug 6, 2026 · Engine, Transmission · IN

"While driving, the vehicle suddenly experienced a flashing check engine light, an Electronic Stability Control (ESC) warning light, and violent steering wheel vibrations. The vehicle suffered a severe loss of power and misfired, creating an immediate traffic hazard. The dealership diagnosed the issue as a catastrophic mechanical lifter failure on the 5.3L V8 Ecotec engine with Dynamic Fuel Management (DFM). Despite the dealer replacing an entire bank of lifters, the engine continues to misfire and vibrate. This premature valvetrain failure at only 36,000 miles is a known design defect that causes sudden engine stalling and disables critical safety features like stability control while the vehicle is in motion, presenting a severe crash risk."

Filed Aug 4, 2026 · Engine · WA

The truck starting making a ticking noise within 24 hours the check engine light was on and it starting shuttering. I got it to the dealership were they informed me of lifters failure, and catastrophic engine failure. Dealer is recommending replacing engine since it's a 2020 and not part of recall.

Filed Aug 3, 2026 · Engine · MN

I brought my truck into a certified GM dealer for recall work on the ground strap. I left the dealership and multiple lights came on dash: check engine light, service ecs, traction control, service parking brake, steering assist reduced. 7 minutes later the engine began miss firing. The dealer asked me to bring it back to the shop and after some digging they discovered my L87, 6.2 engine was missing firing in cylinder 5. Now the motor needs to be replaced and GM is not standing behind the repair.

Filed Jul 17, 2026 · Brakes, Engine · 45,000 miles · OR

The contact’s mother-in-law owns a 2020 GMC Sierra 1500. The contact stated that while her brother-in-law was starting the vehicle, the brake, service engine, and engine warning lights illuminated and the vehicle failed to start. The contact stated that the failure was associated with the federal safety agency Action Number: EA25007 (ENGINE, ENGINE, AND ENGINE COOLING) and PE25001 (ENGINE, ENGINE, AND ENGINE COOLING). The vehicle was towed to a local dealer, where it was diagnosed with engine failure. The vehicle was not repaired. The owner was scheduled to meet with the dealer to discuss the issue. The manufacturer was contacted and confirmed that there were no open recalls on the VIN related to the failure. The failure mileage was approximately 45,000.

Filed Jul 6, 2026 · Engine · WI

The cam shaft bearing failed under normal driving conditions. Many of the service engine lights including brakes and primary service engine light came on after the cam shaft bearing failure. The engine was replaced by a GM dealership at 65,000 miles and was inspected to determine the cam shaft bearing failed. Luckily the engine failed at a speed of 35 mph on an off ramp, as a complete engine failure on the highway could have been much more dangerous. Following the replacement of the engine, within 500 engine miles, O2 sensors in the catalytic converter were replaced and ultimately the catalytic converter had to be replaced as well.

Filed Jun 8, 2026 · Electrical, Engine · MI

- 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!!

Filed May 18, 2026 · Engine · MS

Sitting at a red light and when the light turned green, the engine made a noise and lost power while trying to cross the intersection. The check engine light came on along with some other lights. It was then towed to a mechanic and the engine had to be replaced due to failure of the lifters. The mechanic said it is a common issue with the GM 5.3 engine but unfortunately their has not been a recall.