We purchased our 2018 SLT diesel Terran in September on 2017. It was a very early build and we had just sold back our 2012 VW jetta diesel due to VW fraud. It started out good but after a couple of months, things started going south. First it was the radio would just go dead and nothing could be done to get it back on until it wanted to. Of course, this would never happen at the dealership so nothing has been done to fix it to date. Then about 3000 miles I got a warning that the DEF system was low. After filling DEF, I kept getting different DEF warnings and vehicle shut down warnings. It stooped this for 2 days and on my way to Yuma Az, the warnings all came back, the vehicle went into limp mode and we barely made the last 60 miles to dealership. They found the DEF wire harness was to close to drive shaft and it wore thru the harness and shorted out the system. Back on the road that day. Move forward to August of 2018 and problems again. My wife called and said it quit and I had to leave work to go get her. It started up when i got there and she drove it about 600 yards to truck stop. It was smoking heavily and had no power. I contacted Onstar roadside service and it was towed to nearest dealership. It was diagnosed as a injector failure and then plugged the DOC. We were told the DOC was on BOP and no date when it may show up. After 28 days we were finally notified the vehicle was repaired. They blamed my K&N filter for the issues and removed it. K&N says there is no way and is helping me with this matter. The radio still quits at times and my wife is almost scared to take it any further than work and grocery store. I thought GMC would put out a better product and not have these type of issues. I tried to make a deal trading it in at the dealership we purchased it from but I would have to take a 38% loss in less than a year. I seems they know they cant sell it again.I will go back to foreign vehicles again as I have had much better luck
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. Good thing this is a company car and I can get my company to NEVER DO BUSINESS WITH GM AGAIN. Do not buy this car as the diesel engine is crap and the Dealers have no idea how to deal with it or the weird messages, combined with the check engine light, that show up ion the dash, seemingly translated from Czech.