2018 GMC Terrain Top 3 Complaints and Problems – Is Your Car A Lemon?

Updated on May 1st, 2023 Author: Brian Jones

GMC wants you to believe that they’ve set the standard in the premium small SUV segment, but the complaints regarding their 2018 GMC Terrain are abounding. From regular electrical failures to engine problems, consumers have taken to the internet to file claims. There are also numerous complaints regarding the electronic stability control as well as recalls for the braking system.

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NHTSA Complaints for the 2018 GMC Terrain

Problems with the Electrical System

When you own a newer vehicle, you expect that everything will work the way it’s designed. That’s not what many drivers are finding. Whether it’s the electronics within the cabin or the electrical system that runs the major components, many parts have been reported as being defective.

One owner wrote on Edmunds, “Have had to have the vehicle jump-started twice. OnStar monthly diagnostic report keeps stating ‘LOW BATTERY’ ‘HAVE VEHICLE SERVICED SOON’Been back to the Dealer 5 times. The fourth visit, GM’s Business Resource Center, had a GM Field Engineer attempt to repair the vehicle but he found that the electrical system was ‘within specs.’ He apparently disconnected the battery shutting down all electronic modules to get his ‘within specs’ readings. That was evident when I picked up the vehicle and found that all the pre-set radio stations had disappeared. The dealership has told me several times that GM is aware of the problem and has been working on a solution. They have had other complaints. They have also blamed the cause on ‘too much electronics.’ General Motors also sent me a letter after their ‘Engineer’ attempted the repair which stated. Our attempts to contact you to schedule a final repair opportunity have been unsuccessful. Your Final Repair Attempt case is being closed.”

Another electrical complaint by some owners was related to the back-up camera. GM specifically referred to this situation in their Service Bulletin #18-NA-095. To repair the mirrored image that many people were seeing, the company had to replace the camera and rear license plate lamp wiring.

Hopefully, there weren’t too many accidents before this was repaired. After all, it must have been confusing for drivers to see things backward while backing up; almost like one of those mirror mazes.

Here are some actual complaints logged with the NHTSA about the 2018 GMC Terrain Electrical Problems

THE NAVIGATION/MEDIA CENTER WILL EITHER GO COMPLETELY BLACK OR COMPLETELY WHITE SCREEN EVEN WHEN BACKING UP YOU LOSE THE CAMERA AND CAN’T SHUT OFF THE RADIO. IF THE SCREEN GOES WHITE DURING EVENING DRIVING THE REFLECTION OF THE WINDSHIELD IS SO SEVERE I CAN’T DRIVE AND THE SYSTEM WILL NOT SHUT OFF WHEN THE POWER BUTTON IS DEPRESSED. I HAVE TAKEN IT TO DEALERSHIP, THEY REPLACED THE RADIO ONCE. IT IS DOING IT AGAIN LESS THAN A MONTH LATER. GMC SAID THEY KNOW ABOUT THIS ISSUE WITH THE VEHICLE BUT DO NOT KNOW WHY OR HAVE A FIX. IN THE MEAN TIME I AM TO DRIVE MY VEHICLE SINCE THEY DO NOT SEE THIS AS A SAFETY CONCERN. I HAVE ATTACHED A PHOTO FROM YESTERDAY I WAS IN THE PROCESS OF BACKING UP WHEN THE WHOLE SCREEN WENT BLACK. I WAS BACKING OUT OF MY DRIVEWAY ONTO A CITY STREET. WHEN WE GOT TO OUR DESTINATION AND SHUT THE CAR OFF THE RADIO STAYED ON EVEN ONCE WE EXITED THE VEHICLE AND SHUT AND LOCKED THE DOORS. I AM WORRIED ABOUT THE POTENTIAL OF A FIRE HAZARD AS WELL.

REAR DOOR ELECTRIC LOCKING SYSTEM DOES NOT WORK. ALSO COULD NOT ENTRR CAR AFTER CAR WASH AS ALL OTHER DOORS WERE INOPERABLE.

TL* THE CONTACT OWNS A 2018 GMC TERRAIN. THE CONTACT STATED THAT THE VEHICLE’S ELECTRICAL SYSTEM FAILED. THE VENTS LOCATED NEAR THE INSTRUMENT PANEL EMITTED A STRONG BURNING ODOR WHEN THE HEATING SYSTEM OR AIR CONDITIONING SYSTEM WAS ACTIVATED. IN ADDITION, THE FRONT END OF THE VEHICLE EXHIBITED A STRONG VIBRATION THAT CAUSED THE STEERING WHEEL TO VIBRATE. FURTHERMORE, WHEN THE REAR HATCH DOOR WAS CLOSED, THE REAR HATCH DOOR LIGHT REMAINED ILLUMINATED. THE CONTACT STATED THAT THE REAR DRIVER’S SIDE HUB CLIPS SEPARATED. ON STAR PERFORMED A DIAGNOSTIC AND PROVIDED THE CONTACT WITH DIAGNOSTIC CASE NUMBER: 109309958. THE VEHICLE WAS TAKEN TO RAINBOW NORTHSHORE BUICK GMC (2925 NORTH HIGHWAY 190, COVINGTON, LA 70433, (888) 494-1484) FOR INSPECTION. THE DEALER ONLY CLEARED THE ON START CONNECTIVITY CODES AND INFORMED THE CONTACT THAT THERE WAS A DEFECTIVE MODULE. THE MANUFACTURER DID NOT HAVE A REMEDY FOR THE FAILURE. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS CONTACTED. THE APPROXIMATE FAILURE MILEAGE WAS 4,000.

Problems with the Engine

There were a few engine options available with the 2018 GMC Terrain, but none of them seemed to impress drivers much. Of all the engine options, the diesel seemed to receive numerous complaints.

One driver took to Edmunds to voice concern. Here is what was written. “This diesel engine is crap. Beware. You might be traveling on the Interstate at 70mph when all of a sudden, with no reason or warning; this GMC will throttle you down to 45mph. So, get ready to use your hazards as you rush to the slow lane and hope your GMC Terrain TurboDiesel makes it to the next exit.”

The diesel engine had plenty of faults. In fact, the company issued recall #17337 for vehicles with this engine. GM released a faulty ECM that might not properly diagnose issues with the exhaust particulate matter sensor. To repair it, technicians needed to program the ECM and TCM for proper readings.

It’s scary to drive in a vehicle when the engine doesn’t run properly. There’s nothing more frightening that chugging along on the highway only to have your speeds dramatically decreased. Life literally flashes before your eyes as you worry about getting rear-ended by a tractor-trailer. If this is the standard that GM was hoping to set, we would hate to see what happens in a non-premium lineup.

Here are some actual complaints logged with the NHTSA about the 2018 GMC Terrain Engine Problems

PURCHASED A BRAND NEW GMC TERRAIN. 12 DAYS AND 460 MILES LATER THE SERVICE ENGINE SOON LIGHT CAME ON. TOOK IT TO DEALERSHIP FOR A P050F. THIS IS CODE FOR A LEAK IN THE BOOSTER. THEY DID NOT REPAIR ANYTHING, JUST CHECKED FOR LEAK AND RESET ENGINE LIGHT. AS I READ MORE, THE PROBLEM AFFECTS THE BRAKES ABILITY TO FUNCTION PROPERLY INCREASING DANGER TO DRIVER. THERE IS ALSO DEFECTIVE STOP/IDLE ON THE ENGINE THAT NO LONGER WORKS. I WAS JUST DRIVING DOWN THE ROAD IN TOWN WHEN IT POPPED ON. GM AND YOUNG’S HAVE REFUSED TO REFUND THIS DEFECTIVE VEHICLE.

THE AUTO STOP FEATURE IS A SAFETY HAZARD. ON SEVERAL OCCASIONS WHEN FOOT IS TAKEN OFF BRAKE IT IS SLOW TO MERGE INTO TRAFFIC, AND BEING IN SOUTH LOUISIANA EVEN WITH AC ON HI IT STILL SHUTS DOWN AT TIMES..

Problems with the Electronic Stability Control

When you want to improve stability and traction, you look for a vehicle that offers electronic stability control. This system is specifically designed to make driving seamless, but drivers of the 2018 GMC Terrain don’t think this system is all it’s cracked up to be.

One reviewer on Edmunds stated, “I purchased a brand new 2018 Terrain in May of 2018. Had it for 5 days (approximately 200 miles) before it was towed from my house back to dealership. The car was bucking and braking on its own, would not accelerate and seemed to be slipping gears and not shifting. Got car back after dealership found nothing wrong. This occurs 3 more times, each time worse than the other. Almost caused me an accident on the highway when I went to accelerate to change lanes and the car wouldn’t accelerate at all. After the 4th time it happened I refused to take the car back from the dealership and had to either sue GM for a refund or accept a buy back and get something else. Owned car for 2 months. Only drove it approximately half the time of owning because the rest of the time it was in for service.”

In addition to trouble with this system, GM released Service Bulletin #PIT5481C which points to further issues with the Lane Keep Assist and Lane Departure Warning. It outlines situations when these systems will not work properly, such as when there are vehicles ahead, sudden lighting changes, on banked roads and when the lane markings are poor. So, pretty much anytime you drive

Here are some actual complaints logged with the NHTSA about the 2018 GMC Terrain Electr0nic Stability Control Problems

STOPPED AT A LIGHT TO MAKE A LEFT TURN. THE VEHICLE JERKED, THEN SHIFTED FROM DRIVE TO PARK. THE INFO SYSTEM GAVE ME THE FOLLOWING MESSAGES: TRANSMISSION, STABILITRAK AND PARKING ASSIST. I TURNED THE VEHICLE OFF AND TRIED TO RESTART IT. I GOT A MESSAGE THAT SAID “THIS VEHICLE IS UNSAFE TO DRIVE.:” AT THIS TIME NON OF THE GEAR OPTIONS WERE AVAILABLE. A ROSEVILLE, MICHIGAN POLICE OFFICER HAD TO POSITION HERSELF BEHIND ME BECSUSE CARS WERE GOING AROUND ME ON BOTH SIDES (MY FOUR WAY BLINKERS WERE ON).THE TOW TRUCK DRIVER WAS UNABLE TO PUT THE VEHICLE IN NEUTRAL, THUS MY VEHICLE HAD TO BE DRAGGED ONTO THE TRUCK. AT THE DEALER THEY WERE UNABLE TO CHANGE GEARS AND ONCE AGAIN MY VEHICLE WAS DRAGGED OFF THE TOW TRUCK

DRIVING ON A DOWNSLOPE HEADING NORTH ON 65 GOING INTO TENNESSEE FROM ALABAMA I EXPERIENCED A LOSS OF POWER SYSTEM LIGHTS WENT OFF ALONG WITH GAUGES GOING OFF AND ON. AT WHICH TIME STABIATRAK AND TRANSMISSION LIGHTS CAME ON SAYING TO PULL OVER IMMEDIATELY.WE DID SO CALLED GM ONSTAR WHERE THEY TOLD US WE WOULD EXPERIENCE A LOSS IN POWER BUT COULD TRAVEL ONWARD. WE CHOSE TO GET TOWED, HOWEVER DUE TO THE HOLIDAY WE HAD DIFFICULTIES GETTING A TOW AND WERE FORCED TO DRIVE HOME 90 MILES AWAY. THE PROBLEM DID NOT PRESENT ITSELF AGAIN ON THE DRIVE HOME. WE TOOK IT TO A GMC DEALER IN VESTAVIA HILLS THEY PULLED OFF THE CODES BUT HAD NO REASON FOR THE ISSUE NOR WERE THEY ABLE TO GET SERVICE BULLETINS FROM GM ON THE ISSUE. I DOCUMENTED THE FINDINGS WENT HOME AND A LATER ON 11/23/18 THE PROBLEM OCCURRED AT ABOUT 130 MILES FROM THE FIRST INCIDENT. THIS TIME IT HAPPENED GOING UP A HILL AND GIVING THE CAR GAS DID NOTHING TO GET ME UP THE VERY SMALL GRADE. I HAD TO PUT IT IN REVERSE AND GET A RUNNING START AT THE HILL IN ORDER TO MAKE IT HOME. I CALLED GM AGAIN AND REQUESTED A TOW TO A SECOND DEALER IN TRUSSVILLE, AL THEY WERE UNABLE TO EVEN SEE IT UNTIL MONDAY 11/26/18. I AM VERY FEARFUL THAT IF WE HAVE TO DRIVE IT AGAIN THAT I MAY NOT BE AS LUCKY.

Problems with the Brakes

Stopping a vehicle is a vital action that often is taken for granted. After all, most cars and trucks stop when the operator presses on the brakes. When something is wrong with the braking system, it causes drivers to worry.

Just read what this owner had to say on the NHTSA website. “Bought brand new. At 14,000 miles all 4 rotors are pitted with grooves. Dealer took them apart and found nothing that could cause it. Said they were ‘weathered.’ Took it to 2 other places and said it was a manufacturing defect. Dealer won’t replace because bumper to bumper won’t cover it. It’s a defect didn’t notice until another dealer did the oil change.”
Among this person’s concern, GM also issued recall #18279 because the rear-brake caliper pistons might contain some trapped hydrogen gas. If this is in the brake system, performance is reduced and a crash is more likely. To repair it, technicians need to bleed the brake system and remove all of the gas.

From glitchy electrical systems to brakes that don’t operate properly, there’s a lot to fear when driving a 2018 GMC Terrain. If this is what premium models are made of, it might be better to go with a budget-friendly option instead. At least you will save some money when the systems malfunction.

Here are some actual complaints logged with the NHTSA about the 2018 GMC Terrain Brake Problems

MY COMPLAINT DOES NOT STEM FROM THE DEALERSHIP FIXING THE ISSUE, AS I HAVE NOT BROUGHT THE TRUCK IN YET FOR THE FIX. MY ISSUES LIES IN THE FACT THAT I HAVE TWO YOUNG CHILDREN AGES 3 AND 5 YEARS OLD. I AM NOW STUCK IN A LEASE FOR 3 YEARS KNOWING THE BRAKING SYSTEM IS UNSTABLE. THAT CAUSES ALARMING CONCERN TO ME AND MY WIFE. I DO NOT WANT TO DRIVE THIS CAR WITH MY CHILDREN IN IT AND NOW I HAVE NO CHOICE BUT TO SO FOR THE REMAINDER OF THE LEASE WHICH IS ALMOST 3 YEARS AS I JUST LEASED THE VEHICLE IN JULY. THERE IS NO GUARANTEE THAT THIS CAN’T HAPPEN AGAIN AND I THEREFORE ASK TO BE ABLE TO LEASE ANOTHER VEHICLE AT THE PRICE I AM CURRENTLY PAYING PER MONTH. THE SAFETY OF MY FAMILY IS FIRST AND FOREMOST. UNLESS I RECEIVE A GUARANTEE FROM THE MANUFACTURER THAT THIS WILL NOT HAPPEN AGAIN WITH MY VEHICLE I AM LEFT WITH MORE CONCERNS THAT ONE WHO LEASES A NEW VEHICLE SHOULD BE LEFT WITH.

I PULLED INTO OUR CARPORT. IT FELT LIKE THE CAR JUST “SPED UP AND WENT FASTER AND FASTER.” IT HIT THE FRONT OF THE CAR STRAIGHT ON. NO AIRBAGS DEPLOYED NOR DID THE FRONT END COLLISION STOP HAPPEN.

Your Lemon Law Legal Rights

Think you have a lemon? Sit back and let the experts work out your lemon case at no cost to you. The law makes GMC pay legal fees. You may be able to get your lemon out of your life. Every year, auto manufacturers buy back, replace or pay cash settlements to thousands of ‘lemon’ owners like you.

About the Author:

Brian Jones spent more than 30 years working as an ASE Certified Master Tech and Parts Specialist at multiple dealerships. Brian has become an authority in the industry, traveling across the country to consult for car dealerships and contributing his expertise as a writer for several major automotive publications. In his spare time, Brian enjoys working on pickup trucks, muscle cars, Jeeps and anything related to motorsports.

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