2018 GMC Yukon Reliability Report

Loss of brake assist is the recurring problem. The pedal turns hard, a brake assist warning appears, and stopping distances grow, mostly at low speeds, in parking lots, and right after startup. Dealers trace it to the brake vacuum pump, and some replacement pumps fail again within days. Owners cite earlier vacuum pump recalls and special coverage and argue their trucks should be included. One crash report describes the SUV slowing but not stopping under hard braking. Other complaints cover brakes dragging until they smoked and a false "Service Trailer Brake" alarm with no trailer attached.

Leaking shocks are the main issue. Front magnetic shocks and rear air shocks leak oil, and the ride turns rough, bottoming out or bouncing hard, including while towing a trailer. Failures cluster around 55,000 to 70,000 miles. Replacement parts are often back-ordered or unavailable, leaving some owners renting cars while they wait. Quoted repair costs run from $1,450 to $2500. A few complaints filed here actually describe rear brake squealing and caliper work, or lifter engine failures covered under the engine category.

Power steering assist cuts out, often with a "Service Power Steering" or "Steering Assist Is Reduced" message, and the wheel becomes very hard to turn. Some reports say it fails on cold starts and then returns to normal, which makes dealers hard to convince. One pattern pairs reduced steering assist with StabiliTrak, forward collision, and adaptive cruise warnings at once. Another links lost steering at low speed in left turns to a battery voltage drop. Front-end noises when turning also appear, and dealers frequently find nothing wrong.

Second-row seat belt retractors stop retracting, leaving belts loose. In some cases something inside the retractor rubs and cuts the webbing, and one belt snapped. Replacing both second-row retractors is quoted at $1600. One crash report with 3 injuries says the belt holding a child car seat in the third row did not stay tight. A separate complaint describes the driver seat moving on its own during acceleration, which pushes the driver away from the pedals.

A recurring "Service Trailer Brake System" message pops up and keeps returning after it is dismissed, even with no trailer in use. Rear brake lights also cut out intermittently while driving. One crash report with 3 injuries describes a 30 to 35 mph T-bone collision where the owner believes the airbags should have deployed and suspects a faulty sensor. With only 3 complaints on file, the trailer brake warning is the only repeated problem.

Front airbags failing to deploy in serious crashes is the main concern. Two crash reports describe front or front-side impacts where side airbags fired but the front bags did not, with 4 injuries in total and one fire. A separate report covers a "Service SRS" warning traced to a faulty front passenger seat airbag control module at 50,000 miles. Only 3 complaints are on file here.

Two unrelated failures appear here. One is the AC condenser refrigerant leak seen across this model year, which also disables defrosting; a condenser shield applied as a fix did not stop the leak, and GM declined to pay for the repair. The other is the rear liftgate glass shattering outward while the SUV sat parked, with the support arms extended as if the glass had tried to open. Only 2 complaints are on file.