The 2021 GMC Acadia represents the second-generation platform refresh, still carrying some inherited weaknesses from the GMT C1XX architecture. The 3.6L V6 shows troubling engine failure patterns, while transmission cooling and electronic gremlins round out the main headaches.
Symptoms: Metallic rattling on cold start that worsens over weeks, Sudden loss of oil pressure with engine knock, Check engine light with low oil pressure codes (P0521, P0011, P0014), Metal shavings in oil filter during routine change
Fix: Complete engine replacement or rebuild required — timing chain stretches, wipes cam bearings, then destroys main/rod bearings. Shops see complete oil starvation in upper end. Short block replacement is 18-24 labor hours; full rebuild adds another 8-12 hours. Many opt for reman long block.
Estimated cost: $7,500-12,000
Transmission Oil Cooler Line Failure
Common · medium severity
Typical onset: 40,000-80,000 mi
Symptoms: Transmission fluid leaking from radiator area or cooler line connections, Pink or red fluid pooling under front of vehicle, Transmission running hot (increased shift harshness), Low transmission fluid warning on dash
Fix: The cooler lines crack at crimped fittings or corrode at radiator junction. Requires replacing both cooler lines and sometimes the external cooler itself. 2.5-4 hours labor depending on cooler replacement. Flush system after repair to clear debris.
Estimated cost: $600-1,200
9-Speed Transmission Mount Failure (Front Mount)
Common · medium severity
Typical onset: 50,000-90,000 mi
Symptoms: Loud clunk when shifting from park to drive or reverse, Vibration through floor during acceleration in lower gears, Excessive drivetrain movement visible when rocking vehicle in park, Shudder during 2-3 and 3-4 upshifts
Fix: The front transmission mount tears internally, allowing excessive powertrain movement. Requires removing skid plate and subframe bolts for access. 2-3 hours labor. Replace with OEM mount — aftermarket versions fail quicker.
Estimated cost: $350-550
Electronic Parking Brake Module Failure
Occasional · high severity
Symptoms: Parking brake error message on dash, Parking brake won't release or engage, Grinding noise from rear brakes when applying parking brake, Service parking brake light stays illuminated
Fix: Actuator motor in caliper or control module fails. If caliper actuator, 1.5 hours per side plus brake service. If control module, 2 hours labor plus programming. Module failures often happen with no warning in first 3 years.
Estimated cost: $800-1,400
Backup Camera Failure / Intermittent Display
Common · low severity
Symptoms: Backup camera shows blue screen or 'camera unavailable' message, Image flickers or shows horizontal lines, Camera works intermittently based on temperature, Complete loss of rear vision display
Fix: Camera module failure or corroded connector at liftgate. NHTSA recall covers some VINs but not all. Camera replacement is 1 hour labor, connector repair adds 0.5 hours. TSBs address software glitches — try module reprogram first.
Estimated cost: $300-650
Fuel Vapor Canister Purge Valve Failure
Occasional · low severity
Typical onset: 50,000-100,000 mi
Symptoms: Check engine light with P0496 (EVAP flow during non-purge), Rough idle when fuel tank is full, Fuel smell near driver side rear wheel area, Hard start after refueling
Fix: Purge valve sticks open, allowing fuel vapor into intake constantly. Valve is near fuel tank, 1-1.5 hours labor with wheel and splash shield removal. Sometimes requires replacing canister if charcoal contamination occurs.
Estimated cost: $250-500
Owner tips
If buying a 3.6L V6 model, demand oil analysis history or walk away — engine failures happen suddenly after 60k
Check transmission cooler lines at every oil change — catch leaks before cooler contamination ruins transmission
Update infotainment software to latest version immediately to address camera and connectivity bugs
Inspect transmission mount during tire rotations — catching it early prevents transmission damage
Use only Dexos-approved oil and change at 5,000 mi intervals on V6 — no exceptions
Avoid the 3.6L V6 entirely due to catastrophic engine failure risk; the 2.5L I4 is significantly more reliable but prepare for transmission cooler lines and electronic quirks — budget $1,500/year in repairs after warranty.
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 also compatible; AGM required for start-stop equipped models
As an Amazon Associate, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Every control module on the 2018-2022 GMC Acadia — 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.
📍 Engine compartment, mounted to ABS hydraulic unit on left front frame rail near master cylinder
🔧 GM SPS2 via MDI/MDI2
⚠️ Integrated with hydraulic unit. Brake bleeding required after replacement. Controls ABS, traction control, StabiliTrak.
Body Control Module (BCM)1.5 hr R&Rsecurity gateway +1.0 hr▸ programming details
📍 Behind left side of instrument panel, above fuse block
🔧 GM SPS2 via MDI/MDI2
⚠️ Controls lighting, door locks, wipers, horn, power windows. Extensive configuration required for all body options.
Transfer Case Control Module (TCCM)1.5 hr R&Rdealer / factory tool +0.4 hrAWD models (all Acadias are AWD or FWD; AWD has active transfer case)▸ programming details
📍 Mounted to transfer case on left side
🔧 GM SPS2 via MDI/MDI2
⚠️ Controls AWD engagement and torque distribution. Relearn procedure required.
📍 Engine compartment, rear of engine valley under intake manifold (3.6L V6); right side of engine block near firewall (2.5L I4); left front of engine near battery (2.0L turbo)
Headlamp Control Module (HCM)0.6 hr R&Raftermarket tool +0.3 hrwith automatic headlamps or LED/HID headlamps▸ programming details
📍 Behind left headlamp assembly in engine compartment
🔧 Autel or GM SPS2
⚠️ Controls adaptive lighting and auto high-beam functions when equipped.
Rear Camera Module (RCM)0.5 hr R&Rrelearn only +0.2 hr▸ programming details
📍 Integrated with rear liftgate handle assembly
🔧 GM SPS2 or Autel
⚠️ Standard equipment. Simple relearn typically sufficient unless part of Surround Vision system.
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.
BACK OVER PREVENTION: SENSING SYSTEM: CAMERA · 22V709000
2022-09-22 · PE22006
General Motors, LLC (GM) is recalling certain 2020-2021 Cadillac XT5, XT6, and GMC Acadia vehicles equipped with the optional Surround Vision feature. The rearview camera coaxial cable connectors may have been crimped improperly, causing the rearview camera to fail or function intermittently.
Consequence: An inoperative rearview camera can reduce the driver's rear visibility, increasing the risk of a crash.
Remedy: Dealers will replace the coaxial cables, free of charge. Owner notification letters were mailed January 18, 2023. Owners may contact Cadillac customer service at 1-800-458-8006 or GMC customer service at 1-800-462-8782. GM's number for this recall is N222378380.
FUEL SYSTEM, GASOLINE:DELIVERY:HOSES, LINES/PIPING, AND FITTINGS · 21V422000
2021-06-03
General Motors, LLC. (GM) is recalling certain 2021 Cadillac XT5, XT6, and GMC Acadia vehicles. The fuel supply lines may be improperly attached and seated.
Consequence: Improperly attached and seated fuel supply lines may loosen or separate, causing a fuel leak and increasing the risk of a fire.
Remedy: Dealers will inspect and replace fuel supply lines as necessary, free of charge. Owner notification letters were mailed on July 1, 2021. Owners may contact Cadillac customer service at 1-800-458-8006 and GMC customer service at 1-800-462-8782. GM's number for this recall is N212335590.
Performance
Horsepower
193hp
Torque
188lb-ft
0–60 mph
9.2sec
Quarter mile
16.8sec
Top speed
112mph
Fuel economy (EPA)
City
21mpg
Highway
27mpg
Combined
23mpg
Fuel
Regular Gasoline
Capability & size
Towing capacity
4,000lb
Payload
1,400lb
Curb weight
4,362lb
EPA class
Standard Sport Utility Vehicle 2WD
Wiper blades
Same specifications continue through this generation.
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 Acadia 2.5L I4 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.