The 2020 GMC Terrain, especially with the 1.5L turbo, has earned a reputation for catastrophic engine failures and transmission cooling issues that can turn a seemingly reliable crossover into a financial nightmare. The frequency of short block replacements and connecting rod bearing failures on relatively low-mileage examples is alarming.
Symptoms: Sudden loud knocking from engine bay, Check engine light with misfire codes, Metal shavings in oil, Complete loss of power/engine seizes, Oil consumption between changes
Fix: Complete short block replacement or engine rebuild required, typically 18-24 labor hours. Connecting rod bearings fail prematurely, sending metal through the entire engine. This is a known defect affecting thousands of units. Some owners report multiple failures even after replacement.
Estimated cost: $6,500-9,500
Transmission Oil Cooler Line Failure
Common · high severity
Typical onset: 40,000-90,000 mi
Symptoms: Transmission fluid leaking near radiator, Overheating transmission, Harsh shifting or slipping, Pink/red fluid pooling under vehicle, Burning smell
Fix: Oil cooler lines corrode and rupture, often mixing coolant with transmission fluid and destroying the transmission. Requires cooler line replacement (2-3 hours) if caught early, but often leads to full transmission rebuild or replacement (12-16 hours) if fluids contaminated.
Estimated cost: $400-800 (lines only) or $4,500-6,500 (transmission damaged)
Transmission Mount Collapse
Occasional · medium severity
Typical onset: 50,000-100,000 mi
Symptoms: Clunking when shifting from park to drive, Excessive vibration at idle, Visible engine/trans movement when accelerating, Shuddering during acceleration
Fix: Hydraulic transmission mount fails prematurely, allowing excessive drivetrain movement. Replacement requires 2-3 labor hours. Often overlooked during diagnosis of vibration complaints.
Estimated cost: $350-600
Head Gasket Failure (1.5L Turbo)
Occasional · high severity
Typical onset: 60,000-110,000 mi
Symptoms: White smoke from exhaust, Coolant loss with no visible leaks, Milky oil on dipstick, Overheating, Rough idle and misfires
Fix: The 1.5L turbo develops head gasket failures, often as a secondary failure after oil consumption issues or overheating. Requires cylinder head removal, machining, and reassembly. 10-14 labor hours. Sometimes discovered during short block replacement.
Estimated cost: $2,200-3,800
Excessive Oil Consumption (1.5L Turbo)
Common · medium severity
Typical onset: 20,000-60,000 mi
Symptoms: Low oil warning between changes, Blue smoke on startup or acceleration, Fouled spark plugs, Burning oil smell, Consuming 1+ quart per 1,000 miles
Fix: Piston ring design allows oil to pass into combustion chamber. GM's official stance is 1 quart per 2,000 miles is 'acceptable' but many owners see worse. Often leads to complete engine failure if not monitored. Fix requires piston ring replacement or short block (same 18-24 hours).
Estimated cost: $4,500-8,000
Timing Chain Stretch/Failure (1.5L Turbo)
Occasional · high severity
Typical onset: 70,000-120,000 mi
Symptoms: Rattling on cold start, Check engine light with timing codes (P0016, P0017), Poor performance, Engine won't start, Metal shavings in oil
Fix: Timing chain stretches due to oil consumption issues and inadequate lubrication. Requires timing chain, guides, tensioner, and often VVT components. 8-12 labor hours. Catastrophic if chain jumps timing.
Estimated cost: $2,000-3,500
Owner tips
Check oil level every 500 miles on the 1.5L turbo without exception—oil consumption will destroy the engine
Inspect transmission cooler lines annually for corrosion, especially in rust belt states
Keep detailed service records and fight GM for warranty coverage on engine failures—there are class action lawsuits pending
Consider extended warranty if buying used, or avoid the 1.5L turbo entirely and seek the 2.0L
Hard pass on the 1.5L turbo unless you enjoy surprise $8,000 engine bills—the 2.0L is marginally better, but this generation Terrain has serious reliability issues that make it a poor used buy.
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: AGM battery required for start-stop system; H6 group also fits
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Control Modules — 2020 GMC Terrain
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.
POWER TRAIN:AUTOMATIC TRANSMISSION · 20V668000
2020-10-29
General Motors LLC (GM) is recalling certain 2018-2019 Chevrolet Cruze and Buick LaCrosse, 2018-2020 Chevrolet Equinox, Chevrolet Traverse and GMC Terrain, 2018 Chevrolet Malibu, 2019-2020 Buick Encore, Buick Enclave, Cadillac XT4, Chevrolet Blazer and GMC Acadia, and 2020 Cadillac XT6 vehicles. The start/stop accumulator endcap may have missing bolts.
Consequence: Missing bolts on the start-stop accumulator endcap could result in a transmission oil leak and may progress to a loss of propulsion, increasing the risk of a crash. A transmission fluid leak in the presence of an ignition source may increase the risk of fire.
Remedy: GM will notify owners, and dealers will inspect the start-stop transmission accumulator and replace it if any bolts are missing, free of charge. The recall began December 15, 2020. Owners may contact GMC customer service at 1-888-988-7267, Buick Customer service at 1-866-608-8080, Chevrolet customer service at 1-800-222-1020 or Cadillac customer service at 1-800-458-8006. GM's number for this recall is N202313440.
Vehicle Info — 2020 GMC Terrain
Performance
Horsepower
170hp
Torque
203lb-ft
0–60 mph
9.2sec
Quarter mile
16.9sec
Top speed
112mph
Fuel economy (EPA)
City
26mpg
Highway
30mpg
Combined
27mpg
Fuel
Regular Gasoline
Capability & size
Towing capacity
1,500lb
Payload
1,200lb
Curb weight
3,600lb
Seating
5seats
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 2020 GMC Terrain 1.5L I4 Turbo and can vary by trim.
🔧 Built by master technician Chris Hackleman · Master Technician · 20+ years.