GMC Complaints

The Telematics control module became defective and could not communicate with the BCM and serial data gateway module, causing a check engine light, loss of ONSTAR communications, clock, navigation, and remote vehicle-to-app communication. This part was known to be defective by GM. GM replaced the part starting in 2021 on Escalade models but not others. Service update # N212331730. The TCM became defective less than 24 months after purchase. The dealer stated the vehicle was over mileage for the warranty. The total repair cost was $1846, of which $1110 was labor. Replacement of the TCM was required to clear the check engine light.

Engine had catastrophic failure, engine shut down with no warning while driving at highway speed. Huge vehicle safety concern.

I've now had 2 engines fail catastrophically, One at 19,191 miles and the second failure at 80,661. Both are the 6.2L engine. The first had crank bearings that were black. The second I was not informed of the cause but that it was seized leaving me stranded on the roadside.

My 2020 GMC Terrain (under 100K miles) was running great until one day, after starting the vehicle, I shifted into reverse and felt soft brakes before the engine suddenly shut off. A licensed mechanic diagnosed the issue, pointing to Technical Service Bulletin #PIP5835, which identifies a defective brake vacuum pump. This failure caused damage to the exhaust camshaft and timing belt, ultimately leading to the recommendation of a full engine replacement. GMC’s response? They advised me to pay for their diagnostics and repairs, then file for a "Goodwill Repair," which they admitted was unlikely to be approved. Meanwhile, GM has since replaced this defective vacuum pump with an electric version, acknowledging the flaw—yet leaving owners like me to cover the cost. I believe GM should stand behind their product and take responsibility for this engineering failure, instead of forcing customers to absorb the expense.

I am writing to formally express my dissatisfaction with my 2017 GMC Terrain, which has experienced severe engine failure due to excessive oil consumption. I purchased this vehicle with the expectation of reliability and durability, yet at only 80,000 miles, the engine seized without warning, rendering my vehicle completely inoperable. I have consistently maintained my Terrain according to the manufacturer’s recommended service schedule. However, I recently discovered that the engine was consuming oil at an alarming rate of 1 quart per 1,000 miles, which ultimately led to catastrophic failure. There were no warning lights or clear indicators of low oil, making it impossible for me to prevent the damage. After researching, I have found that numerous other GMC Terrain owners have reported similar excessive oil consumption issues, indicating a potential widespread defect in this engine design. As a loyal GM customer, I am extremely disappointed that a well-maintained vehicle would suffer such a failure at a relatively low mileage. Given the severity of this issue, I request that GM take responsibility for this defect by covering the full cost of engine repair or replacement. A vehicle should not require a complete engine overhaul at 80,000 miles due to a known design flaw. Please provide a prompt resolution to this matter. If GM is unwilling to address this issue, I will have no choice but to explore other options, including filing a complaint with the National Highway Traffic Safety Administration (NHTSA) and seeking legal counsel. I hope to resolve this matter amicably and look forward to your timely response.

While in use on several different occasions, the front windshield wipers malfunction. They stop working for hours sometimes even days. This is a hazard especially if you are in the middle of driving and it’s storming. The a few days ago for instance I was driving and all of a sudden they stopped working while I was driving home in the rain, at night. I had to immediately pull onside the road and wait for the rain to stop because I tried everything to get them to start back working. Including observing and trying to make sure it wasn’t the wiper /signal switch. I even went under the hood and checked to see if the fuse had blown or if there was some kind of wiring undone. Still nothing. I have taken it to the dealership and several people complain about the same thing but no remedy has been presented. They just all of a sudden start back to working out of the blue. This is definitely a safety hazard and these wipers or wiper motor should be recalled and fixed immediately in my opinion. Please help. Save some lives before it’s too late. Thanks for helping with this matter.

Vehicle is put into park after driving. Shift to Park warning comes on while vehicle is in park. Vehicle will not shut off due to this warning and must be left running unoccupied.

Engine was making rattle noises and oil low message appeared. Brought to dealer who changed oil and said they couldn’t detect noises. I asked for a road test and while driving the tech noticed it, then the car died and shifted into neutral without warning.

When carrying the electronic key in my pocket the vehicle will lock/unlock presumably due to the remote contacting other items in the pocket. I have owned well over a dozen GM vehicles and never had this issue. I believe the remote design has the lock/unlock buttons too proud of the surrounding surface

While driving the vehicle shut down and never would restart. It was taken to a GMC dealer and currently on a waitlist for a new engine. The wait period I was given is approximately 4 months as I was told the engine is on back order.