Common Problems with the 2020 GMC Terrain

Powertrain, Transmission Issues:

“In January 2022, I purchased a 2020 GMC Terrain from a local GMC certified dealership along with an extended warranty. In July 2022, I started to experience intermittent acceleration issues. The issue only presented itself upon vehicle startup and was very sporadic. Upon startup, the vehicle was very slow to accelerate even with the gas pedal depressed to the floor. The vehicle would move at an extremely slow rate of speed for approximately 10 to 15 seconds before the vehicle would engage and actually start moving forward at the expected rate of speed. This would happen 4 to 5 consecutive times before things seemed to "warm up" and run smoothly. It proved to be dangerous at intersections if making a left hand turn into oncoming traffic or during heavy traffic times. From the beginning of July to Aug 9th, this has happened on 5 separate occasions. The story is the same, I start the car after it has been sitting for a bit (it's been from several hours to several days) and the issue will present itself without warning. There are no fault or error codes. I've taken the vehicle to my mechanic as well as the dealership where I purchased the car and both have run diagnostics on the vehicle with no luck. My mechanic did drive the car and he experienced the issue first hand but he could not figure out what was wrong. In the event other Terrain owners are experiencing this same sporadic acceleration issue with no fault or diagnostic codes, I wanted to make sure we documented our issue. I did not record the dates of the first few instances but the last two have been July 24th and August 9th.”

“This vehicle is unsafe due to a violent side to side wobble in the front end much like the Jeep death wobble. This happens constantly anywhere from 30mph - 70mph usually after hitting a small bump or when turning hard. The turning aspect is where it has become very dangerous on slippery surfaces as the car then slides out. I live in the mountains where this is a normal occurance. I am actually afraid to drive this vehicle any longer. The dealers have confirmed the issue, but states that GM does not have a fix for this as of now. I have heard this is affecting only the AWD Terrains and equinox platforms. GM has been unresponsive trying to get an answer or getting this fixed. The car has been into multiple dealerships several times for this same issue and has been happening since the car turned about 2400 miles and has been happening more frequently since then for the past 6000 miles.”

“Only a month after purchasing my vehicle I started to feel a wobble in the front end when accelerating up hills and turning while on the gas. I took it to the dealer and they changed out the front tires stating that the problem had been fixed. Once again while driving the problem persisted. I took the car back to the dealer again and they said that they could not find anything wrong and suggested that I make an appointment to go for a drive with the mechanic to show them what is happening. I made an appointment. A day before the appointment I received a call from the dealership stating that an employee recently purchased the same car and they are having similar difficulties. They found online that GMC was requesting information from dealers about the problem and was told that I now need to wait for GMC to come up with a solution. My car shakes every time that I drive it, it's awful, and it only has around 6,000 miles on it. I'm not sure what to do because the dealership told me that I have to wait for a solution. They are not even trying to fix anything at this time. Please help.”

Electrical Problems:

“Radio goes from normal volume to as loud as possible while just driving.scares ya to death! Can't turn volume down with out 1st shutting off radio and turning it back on. Dealership stayed there isn't a problem they could find.Blu tooth cuts in and out and locks the radio up until you shut vehicle off and restart.shows you still on a call even though you have disconnected phone from radio.volume issue has happened several times”

“Dash had gone black intermittently, did not know what speed I was going. OnStar called oor phone multiple to notify us that our airbags we're offline for ten days no warning light on dash until one to two days later. Took to service was informed that gear shift control, engine control module, passenger presence module and airbag sensor needed replaced. All within a month of purchase of said USED vehicle. Fixed under warranty. Then another monther later, got warning on dash saying "conditions not current for shifting", park break light came on, and a p in a yellow circle with a wrench under it came on. Service did fix vehicle, but could not verify message on dash about conditions not favorable... Also recalibrated breaker. Complained numerous times to dealer about these issues and was told "live with it".”

‘While starting vehicle the infotainment screen went black and nothing would work. Stayed this way while driving. Stopped turned off car and still didn't work. Was told it was the data communications module.“

“While driving instrumental panel and infotainment panel completely blacked out for no reason at all. This is the second time in two days this has happened.”

Engine Problems:

“The contact's friend's son owns a 2020 GMC Terrain. The contact stated that while her friend was driving at an undisclosed speed, the brake pedal went to the floorboard while depressed. The brakes failed to immediately stop the vehicle. Additionally, the vehicle made grinding sounds while driving. The vehicle was taken to the dealer, where the vacuum pump, exhaust camshaft, and valve cover gasket were replaced; however, the vehicle lost motive power while driving. The vehicle was towed back to the dealer, where it was determined that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and informed the contact that there was no recall associated with the VIN. The failure mileage was approximately 48,552.”

“I just purchased this vehicle about 2 weeks ago, and was driving through the fog/cold weather and my check engine light came on. Went to O'Reillys and had them check the code. Came up as P0299 (My car was telling me that the engine power was decreased) I had a loss of power I could feel while driving as well. The code said turbo under boost. After I got back into town and the weather was warmer and no fog was present, the turbo started working again. I brought my vehicle into the dealer where I bought it from and they took it to their mechanic and supposedly performed an "update". I will see if I continue to have the same issue in cold weather as I live in Idaho and go to the mountains often.”

“Turbo failed. Car ran fine with no warning lights. Stopped at red light entering interstate and then could not accelerate which left us stuck in traffic. When it did move it would not shift and took over a mile to get above 20mph in a 65mph zone.”

“loss of oil due to engine defect and need new engine. engine and car at dealership. engine has not been torn apart to find cause. occupants could have died because of engine stoppage... GM wants owner to pay over 15,000 for new engine and instillation. car under new car warranty has 24211 miles. no early warning lights of low oil.... Owner took car in immediately when warning lights appeared 9-27-21 and GMC dealership improperly serviced. on 10-14-21 same warning lights reappeared and taken immediately to same close dealership. Now told new engine needed.”

Brakes Problems:

“The contact owns a 2020 GMC Terrain. The contact stated while driving at various speeds, the vehicle lost brake functionality while depressing the brake pedal. The contact stated no warning light was illuminated. The vehicle was towed to a local dealer where it was diagnosed with needing the vacuum pump replaced. The vehicle was repaired however, the failure persisted. The manufacturer was not informed of the failure. The failure mileage was approximately 40,000. The VIN was unavailable.”

“When reversing out of a parking spot, brakes failed causing accident. Multiple attempts to depress brake pedal with no braking. Hit a parked car. After shutting car off and attempting to move vehicle brakes did engage and respond correctly. Rear damage to Terrain occurred requiring towing.”

“Brakes hard to press. Almost cause an accident on interstate. Was able to contain vehicle. Took to autozone to assessed and it said Powertrain System. Brake Booster Senor Circuit.”

Sources: www.nhtsa.gov, carcomplaints.com

California Lemon Law and How Valero Law Can Assist

The California Lemon Law offers essential protection for consumers who have purchased or leased vehicles afflicted by defects, including the 2020 GMC Terrain. If you're grappling with persistent issues that haven't been effectively resolved despite reasonable repair attempts, or if your vehicle has been out of service for a substantial amount of time due to repairs, you might have strong grounds for a Lemon Law case.

Valero Law, a highly regarded Lemon Law attorney firm, specializes in assisting individuals facing challenges like those encountered with the 2020 GMC Terrain. With an in-depth understanding of the complexities within Lemon Law cases, we can expertly guide you through the legal process. Whether it involves negotiations with the manufacturer for a buyback or replacement, or pursuing a legal claim to safeguard your rights, Valero Law is dedicated to advocating for your interests. If the ongoing problems with your GMC Terrain are negatively impacting your driving experience, it's advisable to consider seeking Valero Law's expertise to explore your options and pursue resolution through the California Lemon Law.