2021 GMC SIERRA 1500 Complaints

While driving home, the engine began to run very rough with decreased acceleration, obvious overall loss of power and a significant amount of white smoke being emitted from exhausts. Several alarm indicators and codes started flashing on instrument panel including Check Engine, Service ESC, Steering Assist Reduced, and Service Parking Brake. Had truck towed to dealership. From Dealership Repair Invoice: Truck scanned with diagnostic codes 0300, 0302 present. Dealership removed right side valve cover and found rocker does not move when engine running. They removed the right side head and found cam and lifter damage. Camshaft, and all 16 lifters were replaced as per document 5659832 under warranty. Labor was 23.3 hours plus 1.2 hours to recover and recharge A/C system.

Vehicle will not consistently shut off. Shift to park error received upon trying to shut vehicle off. Concerns on if the vehicle is actually in park and if it is safe to exit vehicle. Concern that vehicle is not in park and electrical units aren’t being properly shut down (i.e. radio).

The contact owns a 2021 GMC Sierra 1500. The contact stated that while The vehicle while operating the vehicle a knocking noise was present coming from the engine and the check engine warning light had remained illuminated. The vehicle was examined by an independent mechanic who diagnosed that the engine valves had malfunctioned and engine needed to be repaired. The vehicle was not yet repaired. The manufacturer was notified of the failure but no assistance was offered. The manufacturer was notified of the failure. The contact was informed that the VIN was not included in the NHTSA Campaign Number: 25V274000(ENGINE AND ENGINE COOLING). The contact indicated that the vehicle had experienced that same failure listed in the recall. The failure mileage was 98,000.

Catastrophic engine failure the connecting rod went through the block. It is my understanding that Defective Components: Manufacturing defects in the connecting rods and crankshafts can reduce oil film strength, leading to severe wear, metal debris, and catastrophic engine could be the proiblem

power steering locked up while driving. has been inspected and repaired by manufacturer. recall.

power steering locked up while driving. multiple dash lights turned on, on its own after the issue, 4wd, emergency brake, abs, and other ones im not sure what they are. took it to the dealership for a recall and told them the issue that happened.

The truck randomly will not detect that it was shifted into park. Shifting between gears and back to park does not automatically fix the the issue and has taken up to 10 mins to turn the truck off. The adaptive cruise controls stopped working and can still use regular cruise control. Just not adaptive. It appears greyed out. The truck has thrown the error code: P1098, Engine Coolant Control Valve Position Sensor Minimum Stop Performance. The truck would go into limp mode until the error was cleared. This error has appeared 4 times over the past five months. The most recent date of it happening was today. 06/30/2026

The truck has a studder that comes from the transmission when at highway speeds. the studder can be felt at random intervals (seconds) from all passengers. The studder is also present on starting up a slope or accelerating from a stop at a slow pace. when accelerating slowly the jerk is more prominent. We have taken it to the GM Dealership, they confirmed the issue was present. The dealership said the GM guidence was to 1st try a re-program and then replace the torque converter. The program flash was unsuccessful, then we paid $4000 to change the torque converter. The Tech stated that this was the GM suggested fix, but noted that we are changing the fluid also which could mask the issue if it is the valve body causing an issue. The replacement torque converter and fluid did somewhat reduce the issue for a short period of about 2 months before it has returned as it did before. The next option from the dealership is in excess of $8,000 for a remanufactured transmission which is outside our reasonable spend, when we dont expect the remanufactured transmission will have any better valve body components. The recent recall did not cover my gas 6.2L sierra 1500, although it clearly is insufficient stating that it just a warning that there is a safety risk present. The valve body of the transmission appears to be an issue across all models and the recall addresses that it is present. We continue to drive this as the primary family vehicle with the hesitation and jerking present as GM dealer offered no support other than $8,000 remanufactured transmission on top of the $4000 we already spent. I believe the recall was insufficent in covering the Gas models with the exact same transmission and known issue. I also believe the offered solution continues to put those driving at risk.

My truck will not start when I press the push-button ignition. After waiting a few seconds and trying multiple times, it typically starts on the third attempt. Additionally, it will not restart after the auto stop feature activates at stop signs or traffic lights. This is very concerning, especially when pulling into oncoming traffic, as I’m worried the truck could shut off while I’m crossing. I have already had the battery, starter, and alternator checked, and all components tested fine. However, the issue is still occurring. There are also no warning lights or messages displayed on the dashboard.

While driving at normal highway speeds, I got a warning light for engine overheat condition and cooling fans came on. I also got a warning that the engine would go to reduced power. I reported this issue to my local GMC dealer. Was told that this was a comm problem with this engine however: my vin number indicated that this vehicle was not covered under warranty N252508341. I was advised to bring it in for a $250 diagnostic check and repairs could not be made for at least 2 months because of backlog. Took my truck to a local vehicle repair shop where they diagnosed a faulty coolant control valve and replaced it for me for $2388.43. Why did GMC desert me?