2015 GMC Terrain Problems: 11 Known Issues

On the 2010-2017 GMC Terrain, the 2.4L LEA and LE9 four-cylinder engines in 2010-2017 Terrain are among the most reported excessive oil consumption issues in GM's lineup. Many owners consume 1 quart of oil every 1,000-2,000 miles. The root cause is inadequate piston ring tension combined with piston ring land fractures that allow oil to bypass rings into the combustion chamber. The problem was subject to class action lawsuits and GM Customer Satisfaction Programs. Burned oil causes spark plug fouling, catalytic converter damage, and oil pressure warnings. This is the same issue affecting the Chevy Equinox with the same engine.

On the 2010-2017 GMC Terrain, first-generation Terrains ordered with the optional V6 - the 3.0L LF1 in 2010-2012 and the 3.6L LFX from 2013-2017 - use GM's High Feature V6 architecture with four timing chains. The chains and their tensioners/guides stretch and wear prematurely, particularly on engines run on the oil-life monitor's long intervals or that have consumed oil between changes and starved the hydraulic tensioners. The ECM detects the resulting camshaft-to-crankshaft phase error and sets P0008 or P0009. This is a completely separate failure from the 2.4L Ecotec timing chain issue already documented: different engine family, different chain count, different repair.

On the 2010-2017 GMC Terrain, first-generation Terrains (2010-2017) are prone to a sudden 'Reduced Engine Power' warning caused by a failing electronic throttle body. Carbon and grime build up inside the bore and the internal throttle position sensor (TPS) fails or reads erratically, causing the ECM to enter a limp/reduced-power mode that limits the vehicle to very low speed. This is a widely reported failure on the naturally aspirated 2.4L four-cylinder and 3.6L V6 engines and frequently appears alongside a 'Service StabiliTrak' message. The most commonly cited trouble code is P2135 (throttle/pedal position sensor voltage correlation). No NHTSA recall covers the throttle body; it is addressed through non-recall repair.

On the 2010-2017 GMC Terrain, the 2010-2017 Terrain uses the GM 6T40 (2.4L) and 6T45 (V6) 6-speed automatic transmissions, both of which suffer from torque converter shudder, harsh shifts, and solenoid failures. The shudder occurs at light throttle between 30-50 mph when the torque converter clutch locks up. Solenoid pack wear causes P0756, P0751, and P0776 transmission fault codes. The transmission is sensitive to fluid condition — the 6T40/6T45 was originally filled with Dexron VI, but older Dexron VI degrades faster than newer formulations.

On the 2010-2017 GMC Terrain, the engine-driven water pump develops bearing/impeller wear or seal leaks, allowing coolant to weep (often visible as dried Dex-Cool on the timing-chain cover or flung from the pump pulley) and eventually causing overheating. On both the 2.4L Ecotec and 3.6L V6, the pump is timing-chain-cover-mounted, making replacement labor-intensive and comparatively expensive. Neglecting a leaking pump can damage timing components.

On the 2010-2024 GMC Terrain, terrain front and rear hub assemblies integrate the ABS magnetic encoder ring into the bearing's inboard seal, where it sits directly exposed to road salt and moisture. Two distinct failure modes result. The mechanical one is the familiar humming or roaring that rises with speed and changes when loading the bearing in a wide turn. The one that fools owners and shops is encoder-ring failure on a bearing that is still mechanically tight and silent: the wheel speed signal drops out and the vehicle sets a wheel speed sensor code with ABS, traction control and stability control disabled. Replacing only the external sensor does not fix it, because the encoder is part of the bearing. Both generations are affected, with salt-belt vehicles failing earliest.

On the 2010-2017 GMC Terrain, gM recalled 740,581 first-generation Terrains because an internal reflection in the headlamp housing throws excessively bright light above the beam pattern and outside the driver's own field of view. The vehicles do not comply with Federal Motor Vehicle Safety Standard 108. The stray upward light dazzles oncoming and preceding drivers, reducing their visibility and increasing crash risk. This affects the entire 2010-2017 run, making it one of the largest single actions ever taken on this nameplate, and it is not related to any bulb or wiring failure - the housing optics themselves are the defect.

On the 2010-2017 GMC Terrain, sunroof-equipped first-generation Terrains use a drain trough around the glass panel with four hoses routed down the A-pillars and out through the rear body-side extensions. The original-design hoses are small in diameter and prone to clogging with debris and factory sealant residue; owners commonly find three of four drains blocked. The hoses also shrink with age and pull off the sunroof module fitting. Once a drain backs up, water overflows the trough into the headliner and runs down onto the front or rear carpet. GM issued a service bulletin covering wet floors and interior water leaks on 2010-2017 Equinox and Terrain that specifically identifies the smaller-diameter older-design drain hose as clog-prone. Left alone, the standing water corrodes floor-mounted modules and connectors and creates mold.

On the 2013-2019 GMC Terrain, the IntelliLink/MyLink touchscreen freezes and spontaneously reboots, losing control of radio, climate, navigation and Bluetooth, and often displays a black screen or a frozen backup-camera image. During a reboot, phone calls drop and the rear camera can go dark while in reverse - a visibility concern. Root causes include software glitches, outdated firmware, and occasionally loose display/camera wiring.

On the 2010-2017 GMC Terrain, the HVAC blend/mode-door actuators fail as their internal plastic gears strip, producing a repetitive clicking or knocking sound from behind the dash and causing loss of temperature or airflow control. On dual-zone systems one side commonly blows hot while the other blows cold, or the system sticks on one temperature. A click/pop typically means a stripped gear requiring replacement.

On the 2010-2017 GMC Terrain, the fuel level sensor in the in-tank pump module is a potentiometer whose wiper rides on a resistor card. Sulfur compounds in pump gasoline plate onto the card, and varnish builds on the float arm pivot, so the sender's resistance no longer tracks actual tank level. First-generation Terrain owners report gauges that never rise past three-quarters, gauges that drop an eighth to a quarter of a tank within five miles of filling, and gauges frozen on empty with the low-fuel light on. Forum threads also document the fuel module seating in the tank shell at an orientation that prevents the float from reaching the full-travel position. The consequence is running out of fuel unexpectedly rather than any warning light.