The 2021 GMC Terrain, particularly with the 1.5L turbo, suffers from catastrophic engine failures due to piston ring and connecting rod issues, often requiring complete engine replacement. The 9-speed transmission also shows premature wear and cooling system failures that strand owners.
Symptoms: Excessive oil consumption (1 quart per 1,000 miles or worse), Metal shavings in oil during changes, Knocking or ticking noise from lower engine block, Check engine light with misfire codes, Sudden catastrophic failure with connecting rod through block
Fix: Complete engine replacement or short block required; 12-16 hours labor. GM extended warranty to 120k miles on some VINs, but many owners pay out-of-pocket. Root cause is defective piston ring design causing oil burning that leads to rod bearing failure. Repair involves complete engine R&R.
Estimated cost: $6,500-9,500
9-Speed Transmission Shudder and Oil Cooler Failure
Common · high severity
Typical onset: 30,000-70,000 mi
Symptoms: Hard shifts or delayed engagement from stop, Shuddering during light acceleration at 20-40 mph, Transmission fluid in coolant or coolant in transmission, Overheating transmission warning light, Loss of drive or limp mode
Fix: Transmission oil cooler replacement (integrated into radiator) requires 4-6 hours; often causes cross-contamination requiring full trans rebuild if coolant entered. Shudder issues may need torque converter or full transmission replacement at 10-14 hours. TSBs exist but fixes are temporary.
Estimated cost: $1,200-5,800
Transmission Mount Failure
Occasional · medium severity
Typical onset: 50,000-80,000 mi
Symptoms: Clunking when shifting from park to drive/reverse, Excessive vibration at idle, Visible sagging of transmission, Harsh engagement during gear changes
Fix: Side transmission mount deteriorates prematurely, especially on AWD models. Replacement requires 2-3 hours; access is tight and may need subframe partially dropped. Use OEM mount as aftermarket fails quickly.
Estimated cost: $350-600
Head Gasket Failure (1.5L Turbo)
Occasional · high severity
Typical onset: 60,000-100,000 mi
Symptoms: White smoke from exhaust on cold start, Coolant loss with no visible leaks, Overheating under load, Bubbles in coolant reservoir, Milky oil on dipstick or filler cap
Fix: Head gasket replacement requires cylinder head removal; 8-12 hours labor. Often find warped head requiring machining or replacement. Common on engines that survived piston ring issues due to excessive heat cycles. Head bolts are TTY (torque-to-yield) and must be replaced.
Estimated cost: $2,800-4,200
Fuel Filter Premature Clogging
Occasional · medium severity
Typical onset: 40,000-70,000 mi
Symptoms: Hard starting or extended cranking, Loss of power under acceleration, Rough idle or stumbling, Check engine light with fuel trim codes
Fix: In-tank fuel pump module with integrated filter clogs early, especially with ethanol fuels. Requires fuel tank drop; 3-4 hours labor. Not serviceable separately, need entire pump assembly. GM part quality varies by supplier batch.
Estimated cost: $600-950
Timing Chain Stretch (1.5L Turbo)
Occasional · high severity
Typical onset: 70,000-110,000 mi
Symptoms: Rattling noise on cold start for 2-3 seconds, Check engine light with cam/crank correlation codes, Rough running or misfires, Metal debris in oil
Fix: Timing chain and tensioner failure requires front engine disassembly; 8-10 hours labor. Often find damaged chain guides. If oil consumption wasn't addressed early, timing system fails from oil starvation. Must replace chain, guides, tensioners, and gears as assembly.
Estimated cost: $2,200-3,400
Owner tips
Check oil level every 1,000 miles religiously on 1.5L turbo; consumption over 1 qt per 3k is grounds for warranty claim
Change transmission fluid every 50k miles despite GM calling it 'lifetime fill' — prevents shudder and cooler issues
Verify if your VIN is covered under GM's extended piston warranty (PIP5753) before buying used
Run compression and leak-down test during pre-purchase inspection — these engines fail without warning
Avoid the 1.5L turbo entirely if possible; 2.0L turbo has fewer catastrophic failures but less common in base trims
Hard pass unless heavily discounted with documented proof of engine replacement under warranty — the 1.5L turbo is a ticking time bomb that makes this generation Terrain a financial liability.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.
Fitment notes: H6 group may also fit; AGM battery required for start-stop system
As an Amazon Associate, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Every control module on the 2018-2024 GMC Terrain — where it lives, replacement time, and what it takes to program a replacement. Modules marked dealer / factory tool won't work after a part swap alone — budget for programming.
📍 9-speed automatic: integrated with valve body inside transmission (TEHCM - Transmission Electro-Hydraulic Control Module)
🔧 GM SPS via GDS2/MDI or MDI 2
⚠️ Requires transmission pan removal, fluid drain, and valve body disassembly. VIN programming, adaptive relearn, and security gateway authentication required. 9-speed transmission standard across all models.
Body Control Module (BCM)2.8 hr R&Rdealer / factory tool +1.0 hr▸ programming details
📍 Behind center of instrument panel, above center console, mounted to HVAC plenum bracket
🔧 GM SPS via GDS2/MDI or MDI 2
⚠️ Requires instrument panel top cover removal. VIN programming, theft deterrent relearn, security gateway authentication, and security linking with ECM/SDM required. All power accessories and options must be reconfigured. Critical security module.
Electric Power Steering Control Module (EPSCM)2.2 hr R&Rdealer / factory tool +0.5 hr▸ programming details
📍 Integrated with electric power steering motor assembly on steering column, below instrument panel
🔧 GM SPS via GDS2/MDI or MDI 2
⚠️ Steering column must be partially disassembled. VIN programming, steering angle sensor calibration, and security gateway authentication required after replacement.
📍 Behind center of instrument panel, near BCM, mounted to HVAC plenum
🔧 GM SPS via GDS2/MDI or MDI 2 with security access
⚠️ VIN programming and security gateway authentication required. Controls security access to all modules on vehicle network. Critical security module. Replacement requires dealer-level tools in most cases.
📍 Behind center of instrument panel, near radio, mounted to HVAC plenum
🔧 GM SPS via GDS2/MDI or MDI 2
⚠️ Camera calibration and dynamic guidelines configuration required. Processes feeds from four cameras (front, rear, both mirrors). Rear camera standard on all models; surround vision optional.
OnStar Communication Module / Vehicle Communication Interface Module (VCIM)1.8 hr R&Rsecurity gateway +0.6 hr▸ programming details
📍 Behind center stack, above radio assembly, mounted to HVAC plenum
🔧 GM SPS via GDS2/MDI or MDI 2 with security access
⚠️ VIN programming, security gateway authentication, and OnStar account linking required. Security-critical module. 4G LTE Wi-Fi hotspot capability. Aftermarket tools have very limited success.
Remote Control Door Lock Receiver (RCDLR)1.8 hr R&Rsecurity gateway +0.5 hr▸ programming details
📍 Behind center of instrument panel, near BCM, mounted to HVAC plenum
🔧 GM SPS via GDS2/MDI or MDI 2 with security access
⚠️ VIN programming and security gateway authentication required. Handles remote keyless entry, remote start, and push-button start signals. Security-linked with BCM and gateway. Aftermarket tools have limited success.
Fuel Pump Control Module (FPCM)1.8 hr R&Rno coding▸ programming details
📍 Under vehicle, mounted to fuel tank top, integrated with fuel pump assembly
⚠️ Fuel tank must be lowered. Fuel system depressurization required. Module controls variable fuel pump speed based on ECM commands.
📍 Engine compartment, driver side frame rail near strut tower, integrated with ABS hydraulic unit
🔧 GDS2/MDI or Autel/Launch
⚠️ Brake system bleeding required. Automated bleed procedure via scan tool recommended. StabiliTrak, traction control, and hill start assist integrated. Electronic parking brake control on some models.
📍 Behind left side of instrument panel, near BCM location
🔧 GDS2/MDI or Autel/Launch
⚠️ Trailer brake gain calibration required. Integrates with EBCM for coordinated braking. Trailer sway control and trailer tire pressure monitoring on some models.
Forward Collision Alert / Adaptive Cruise Control Module (FCA/ACC)1.5 hr R&Rdealer / factory tool +0.8 hrwith Forward Collision Alert or Adaptive Cruise Control (SLT/Denali trims)▸ programming details
📍 Behind front grille, center, mounted to radiator support
🔧 GM SPS via GDS2/MDI or MDI 2
⚠️ Radar calibration and aiming required after replacement. Requires specific alignment equipment. Controls forward collision alert, automatic emergency braking, adaptive cruise control, and following distance indicator. Lane keep assist uses camera in mirror.
📍 Engine compartment, driver side firewall, mounted to bracket below brake master cylinder
🔧 GM SPS via GDS2/MDI or MDI 2
⚠️ VIN programming, theft deterrent relearn, and security gateway authentication required. 1.5L turbo and 2.0L turbo engines use different ECM hardware.
Infotainment Control Module / Radio (ICM)1.2 hr R&Rdealer / factory tool +0.5 hr▸ programming details
📍 Behind center stack, integrated with touchscreen display assembly
🔧 GM SPS via GDS2/MDI or MDI 2
⚠️ VIN programming and security gateway authentication required. 7-inch or 8-inch touchscreen depending on trim. Apple CarPlay and Android Auto standard. OnStar and navigation features require activation.
Liftgate Control Module (LGM)1.2 hr R&Raftermarket tool +0.3 hrwith power liftgate▸ programming details
📍 Inside liftgate, driver side, behind interior trim panel
🔧 GDS2/MDI or Autel/Launch
⚠️ Liftgate position relearn and height programming required after replacement. Hands-free operation standard on most trims with power liftgate.
📍 Center console, below center stack, mounted to floor tunnel
🔧 GM SPS via GDS2/MDI or MDI 2 with security access
⚠️ VIN programming and security gateway authentication required. Security-linked with BCM. Crash data retrieval capability. Wait 2 minutes after battery disconnect before handling. Aftermarket tools have limited success.
Parking Assist Control Module (PACM)1.0 hr R&Raftermarket tool +0.3 hrwith front/rear park assist▸ programming details
📍 Behind rear bumper fascia, center, mounted to bumper reinforcement
🔧 GDS2/MDI or Autel/Launch
⚠️ Sensor calibration required after replacement. Front and rear park assist standard on most trims. Integrates with surround vision on equipped models.
Door Control Module (DCM)1.0 hr R&Raftermarket tool +0.2 hr▸ programming details
📍 Inside each front door, lower section, behind door trim panel
🔧 GDS2/MDI or Autel/Launch
⚠️ Window auto-up/down calibration required. One module per front door. Memory seat functions may require additional programming.
⚠️ VIN programming and security gateway authentication required. Mileage transfer from old module required by law. Digital cluster on higher trims. Theft deterrent relearn may be needed.
Headlamp Control Module (HCM)0.8 hr R&Raftermarket tool +0.2 hrwith LED or HID headlamps▸ programming details
📍 Engine compartment, behind driver side headlamp assembly
🔧 GDS2/MDI or Autel/Launch
⚠️ Headlamp aim calibration may be required. Controls adaptive lighting functions on equipped models. Standard halogen headlamps do not use this module.
⚠️ Seat position calibration required. Integrates with driver door module for memory recall. Heated and ventilated seat functions integrated.
Tire Pressure Monitor Control Module (TPMS)no coding▸ programming details
📍 Function integrated into BCM; no separate module
⚠️ TPMS sensor programming handled by BCM. Sensor relearn required after tire rotation or replacement.
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
General Motors, LLC (GM) is recalling certain 2020-2023 Chevrolet Equinox and GMC Terrain vehicles. The four rear-seat lower child seat LATCH anchorage bars may have excessive powder coating, which could prevent a child seat from being installed with the anchorage bars. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 225, "Child Restraint Anchorage Systems."
Consequence: The inability to install a child seat with the LATCH anchorage bars could result in an unsecured child seat, increasing the risk of injury in a crash.
Remedy: Owners are advised to install child seats using the vehicle's rear seat belts until the remedy is complete. Dealers will inspect the latch anchorage bars, and remove and replace the finish, as necessary, free of charge. Owner notification letters were mailed June 2, 2023. Owners may contact Chevrolet customer service at 1-800-222-1020 or GMC customer service at 1-800-462-8782. GM's number for this recall is N232403240.
TIRES · 21V612000
2021-08-05
General Motors, LLC (GM) is recalling certain 2021-2022 Chevrolet Equinox and GMC Terrain vehicles equipped with certain Hankook tires. The tires may have been manufactured with an insufficient amount of curative agent, which could cause tread separation.
Consequence: Tread separation can result in a loss of vehicle control, increasing the risk of a crash.
Remedy: Dealers will inspect the tire DOT numbers, and replace any affected tires, free of charge. Owner notification letters were mailed on August 31, 2021. Owners may contact GMC customer service at 1-800-462-8782; and Chevrolet customer service at 1-800-222-1020. GM's number for this recall is N212343560.
Performance
Horsepower
170hp
Torque
203lb-ft
0–60 mph
9.2sec
Quarter mile
16.8sec
Top speed
112mph
Fuel economy (EPA)
City
25mpg
Highway
30mpg
Combined
27mpg
Fuel
Regular Gasoline
Capability & size
Towing capacity
1,500lb
Payload
1,100lb
Curb weight
3,615lb
EPA class
Small Sport Utility Vehicle 2WD
Wiper blades
Second generation (2018+). J-hook attachment standard.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 2021 GMC Terrain 1.5L I4 Turbo and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.