2020 GMC Sierra 1500: multiple warning lights

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 Apr 29, 2026 · Engine · NC

Driving on highway, engine light came on with many warning lights. Was just starting on a trip to SC then OH to help father for a surgery. Lifters went bad within fist 5-6k miles on the truck (6.2L) causing other damage to the engine such as bent rods (etc). Dealer repaired all DFM Lifters as there were failures on both sides of the engine, but it still sounds like there are issues internally. It is a 2020 manufactured in 2019, I have not had additional mechanical issues, but I have purposely not driven it as much since I feel that it is not dependable. It currently only has about 27k miles and sounds worse than my 2007 Lexus engine with 180k+ miles. I wanted to fill this out, so you have the data for the engineering investigation.

Filed Nov 12, 2025 · Engine · IN

This is a report on an incident that happened a year ago. Vehicle was taken to GMC dealer who replaced the engine at our expense. Seems to be consistent with the problem on newer GMC's that have been covered by a recall. This 2020 is one of three GMC's owned by our company. This expense was in the $12,000 range. (The 2019 experienced similar issues in 2022 and the expense was $2800 ish, and in 2024 another $1200 ish. ) Dash lit up like a Christmas tree, all warning lights on. Stalled, barely moved.

Filed Oct 28, 2025 · Engine · 19,000 miles · WV

The contact owns a 2020 GMC Sierra 1500. The contact stated that while driving 55 MPH, the vehicle failed to accelerate as intended while depressing the accelerator pedal. In addition, there was an abnormal sound coming from the engine. Multiple warning lights were illuminated. The contact was able to coast to the side of the road. The vehicle was towed to the dealer, where it was diagnosed with engine failure. The engine was repaired. Most recently, while driving 35 MPH, the vehicle failed to accelerate as intended while depressing the accelerator pedal, with an abnormal sound coming from the engine. Multiple warning lights were illuminated. The vehicle was towed to the dealer, where it was diagnosed with engine failure. The contact was informed that the camshaft, bearings, and lifters in cylinder #4 had failed. The vehicle remained at the dealer unrepaired. The manufacturer was notified of the failure. However, no assistance was provided. The failure mileage was approximately 19,000.

Filed May 22, 2025 · Engine · MI

No warning; picking up child from daycare. went to depart daycare when my dash lit up like a Christmas tree with various errors, alerts, warnings; along with, not being able to start. had to be picked up by spouse and get the truck towed to the dealership for maintenance. Maintenance tech discovered that the grounding straps for the truck needed to be replaced / resulting in a complete electrical failure of the vehicle.

Filed May 4, 2025 · Engine · AZ

I was driving on the frontage road that enters the freeway when then engine suddenly failed and stalled. It lost power and seemed like it was misfiring. All the warning lights on the dashboard came on as this happened but there were no warnings lights, messages, or symptoms before this happened. The sudden loss of power posed a risk to my safety because it could have caused a crash or left me stranded. I had my vehicle towed to the Freeway Chevrolet dealer in Chandler, AZ where they inspected the vehicle and confirmed the engine had a camshaft and lifter failure.

Filed Jan 23, 2025 · Engine, Fuel system · WA

On January 8th I was driving when my 2020 GMC Sierra 1500 Denali started to misfire as well as several warning lights blinking. I happen to be a couple miles from the dealership I purchased it at so I drove it straight there. A few days later I was notified it was the lifters that went bad and it would cost $5400 plus tax. This is disturbing since I have only had my truck for a little over 4 years with 68,000 miles on it. After researching the problem it appears that its a common issue and I notices a class action lawsuit for this reason. Since it's not recalled currently I'm stuck covering the invoice. Before the problem happened my truck was driving normal and no warning lights came on. This needs to be investigated so the consumer isn't stuck paying for something that is an obvious GM issue .

Filed Jan 18, 2025 · Electrical, Engine · AK

On [XXX], I was driving my truck on [XXX] through Phoenix, AZ. It was 5 days after I had purchased the vehicle and only had 250 miles on the odometer. I was in the left lane was traveling at approximately 75mph. Within the span of about 20 seconds, several lights on the dash annunciated and several messages including a message about a brake failure and steering assist failure and then the engine suddenly turned off. The steering seemed heavy and the brakes seemed less responsive. I was able to coast to a stop on the side of the road thanks to the help of a couple truckers who blocked traffic across multiple lanes. The truck was towed to the dealer and they told me the entire engine needed to be replaced. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed May 9, 2024 · Electrical, Engine · LA

My wiring harness which affects all systems. I was on the Interstate when out of nowhere any and all warning lights came on. The power was cut and rapidly slowed down. I also pulled into traffic and the truck just lost power. The problem was confirmed by dealership. The vehicle was inspected by dealership and wiring harness was the issue. The issues appeared out of nowhere. All the warnings lights came on at once. There has been numerous issues with this part and it’s even recognized by just.

Filed Jan 20, 2023 · Brakes, Electrical · FL

I own a 2020 GMC Sierra 1500 4-Cyl, Turbo, 2.7 Liter with 20K miles and I owned the truck for almost 2 years. All of a sudden my vehicle started receiving multiple warning messages. While driving I stopped, and when traffic stopped in front of me the engine died all the lights were on warning messages on the dashboard started showing up. Electronic Stability Control, Antilock Braking System, ECM, reduced Engine Power, etc., and the brakes were hard to step on it and the steering wheel hard to turn,I took my foot off the brakes and pressed it again to start. It started but the check engine light was still on, this happened FOUR times already and THREE times while parked when I tried to start, after a few tries giving few minutes intervals, it will start with all the lights on and warning messages on the dashboard start showing up. Electronic Stability Control, Antilock Braking System, ECM, reduced Engine Power, etc., and the brakes were hard to step on it and the steering wheel hard to turn.

Filed May 23, 2021 · Brakes, Engine · TX

On Saturday, May 22, 2021, My wife was returning from fairgrounds in Waxahachie, TX. She remote-started the car, and the vehicle started. As it started to rain and was getting muddy, and the grounds are in a grass field (No large rocks, hills or debris to climb as it's cleared land), she shifted the vehicle into 4wd high incase the field was slick. She started to drive and received several warning lights, "Service ESC, Service traction control, brake light warning and check engine light". The vehicle also had a noticeable wobble to the wheel and felt off balance, jerky, and had speed limited. My wife turned the vehicle off and back on and some of the lights went off, and the vehicle did not lurch or wobble anymore. The vehicle had a tire changed at the dealer the day prior, so I am unsure if that tire change is related or not. Now the vehicle shows an alert "check engine, service emissions system". I am having the vehicle towed to the dealership tomorrow for diagnostics. All lights except the check engine light have since turned off since powering off the vehicle.

Filed Sep 23, 2020 · Brakes, Electrical · 5,000 miles · CA

Everything was fine for about 6 months after having purchased vehicle as new. Then I got warning lights asking me to both service the parking break and service ESC with a warning that driving would be compromised just over 60mph. I notified dealer who says they fixed the glitch but it happened again. The last time, most recently, I tried to start the truck the next day and all the warning lights came on. This was followed by a complete shut down. No engine, no lights - not even lock/unlock with key fob. It had to be towed. This is a 2020 vehicle and seems like it will strand me some place at the very least. Awful, expensive, and perhaps deadly dynamics here. Gmc, get your act together. You owe us immediately. Provide the fix immediately or give me money back with no contest.