GMC Complaints

Vehicle went into limp mode while driving on the highway. Onstar said it was the transmission. Checked the oil and smoke was billowing out of the dip stick and there was no oil. None of the sensors indicated that there was low oil. After sitting and waiting for a tow truck rechecked the oil with the dipstick and there was oil in it. Now requires a new engine.

Rear tailgate on my 2021 Sierra opens or drops when wet. This seems to only happen in a heavy rain or after a truck wash. This problem has been recognized by the manufacturer and the dealer. There is no warning other than the constant clicking of the electric switch allowing the tailgate to drop. This problem has been recalled on the 3/4 & 1 ton trucks but not the 1/2 ton. The tailgate and switches are the same on all 3. Because my vin# does not show for this recall I had to pay for the replacement

My vehicle was one of the vehicles that was subject to the engine failure recall by GM. I took it to the dealership for the “repair“ where I was told the oil was changed to a different weight. Last night, I was driving down the road and all of a sudden my car just stopped. It still had power, but the engine had stopped. I tried to restart was unable to.

Owner of a 2019 GMC Acadia Denali (VIN: [XXX] , current odometer ~87,164 miles), purchased new. In early February 2026, the check engine light came on. Independent diagnostic scan confirmed persistent P0420 code (“Catalyst System Efficiency Below Threshold Bank 1”) as current, history, pending, and permanent. Inspection showed the front exhaust pipe bracket had snapped, damaging the flex pipe and causing an exhaust leak. This failure mode directly triggers the P0420 code and requires replacement of the bracket and affected flex pipe section. This is a known recurring issue on GM’s Lambda-platform vehicles (shared platform, 3.6L V6 engine, and exhaust system design). GM Special Coverage Adjustment N212356540 covers 2019 Chevrolet Traverse and Buick Enclave models for front exhaust pipe bracket separation (resulting in pipe damage, holes, leaks, rattling, or efficiency codes), providing free repair for 15 years or 150,000 miles from in-service date, regardless of ownership. The failure on this Acadia is mechanically identical, yet the model is excluded from coverage despite matching part design and numerous similar owner complaints documented on NHTSA and BBB reports. Multiple attempts were made to resolve through the selling dealership (no response to service inquiries). Matter was escalated to GM Executive Resolution. GM required a redundant diagnostic scan at an authorized dealer (additional cost incurred), despite independent confirmation of the issue. GM ultimately denied any coverage, TSB applicability, goodwill assistance, or further support. The snapped bracket and resulting exhaust leak can produce noise, fumes in cabin, potential component damage, and emissions noncompliance via false/legitimate catalyst efficiency codes. Inconsistent application of coverage for the identical defect across equivalent Lambda-platform models raises concerns about a widespread safety/emissions issue affecting 2019 GMC Acadia. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The control knob that controls AWD, 2WD,Off-road, and 4 x4 AWD. Just stopped working. Stuck on 2WD mode. I did have it checked for any codes, even though, there is NO check engine light is on.

TRANSMISSIONS ISSUES. Not transitioning/ shifting into gears smoothly or at all. When it does transition/shift it is rough and harsh. When my car transitions to a lower gear then it will not transition back up to a higher gear causing my vehicle to drop speed significantly that I am a safety hazard on the road. Example: when it shifts to a gear high enough that the vehicle can reach 40 mph and there is a need to decelerate it does but once it drop to lower gears it cannot engage again to a higher gear leaving me stuck going at most 10 mph with not opportunity to excelerate in traffic to a higher speed. The transmission control module (TCM) software was updated with no improvement.

Engine developed a low knock type noise just above idle while beginning to move in the parking lot. It was also noted pulling away from an intersection at low rpm under light acceleration. Oil pressure was normal, 30 psi and approximately 50-60 at cruising speed. Low level knock began earlier in the day but no other symptoms. Oil level was checked and found to be at proper level. At mile 2 into my trip a chirping/ squeak type noise was heard under light throttle and light load at approximately 1500 rpm. The noise stopped when accelerator was released. Rough running sensation followed the noise under the load. Noise returned when the accelerator was pressed and then the engine stopped running while traveling 45-50 mph. Placed the shifter to neutral and attempted to restart, engine rolled slowly for a brief moment and then locked up entirely. Starter only clicks when attempted after that. Vehicle left me stranded with no heat on the shoulder of the highway in the dark in Northern Michigan on March 5, ambient temp was 28 degrees. Vehicle towed to closest dealership which is also where it was purchased for inspection on 3/6/2026. General motors customer care contacted and case opened. No assistance with repair at time of callback.

The contact owns a 2020 GMC Acadia. The contact stated that the doors failed to open from outside the vehicle while using the key fob or while attempting to open the doors manually. The contact entered the vehicle from the rear hatch door and discovered that the door lock and unlock buttons were inoperable. The contact pulled the door handle to manually open the door from the inside. The cause of the failure was not yet determined. The manufacturer and local dealer were notified of the failure, but no assistance was provided. The failure mileage was 68,140.

Exhaust fumes and stink on cold start . vehicle only has 40,000 mi and I have exhaust smells coming in through hvac system!!

Getting off on highway and when I got to the light the truck stuttered and shut off. will not turn back on. when I try to start it it stutters and will not turn on