The 2021 Colorado is a mid-size truck that shows significant reliability splits by powertrain — the 3.6L V6 is generally solid, the 2.5L I4 is adequate but underpowered, and the 2.8L Duramax diesel has proven catastrophically problematic with widespread engine failures requiring complete rebuilds or replacements.
2.8L Duramax Catastrophic Engine Failure
Common · high severity
Typical onset: 60,000-120,000 mi
Symptoms: excessive oil consumption (1 quart per 1,000 mi or worse), white or blue smoke on cold start, loss of power under load, metal shavings in oil, connecting rod bearing noise (knocking), eventual complete seizure
Fix: GM issued TSB PIP5748 acknowledging piston ring issues and crankshaft bearing failures. Most cases require complete short block replacement or full engine rebuild with updated pistons, rings, crankshaft, and bearings. 18-24 labor hours for short block swap, longer for full teardown rebuild. Many engines grenading before 100k miles.
Estimated cost: $12,000-18,000
Transmission Oil Cooler Line Failure
Common · medium severity
Typical onset: 40,000-80,000 mi
Symptoms: transmission fluid leaking near radiator, pink fluid pooling under front of truck, transmission overheating warnings, fluid cross-contamination if cooler ruptures internally
Fix: The auxiliary transmission cooler lines corrode and crack where they connect at quick-disconnect fittings. Replace both supply and return lines, flush system if coolant contaminated trans fluid. 2.5-3.5 labor hours.
Estimated cost: $450-750
8-Speed Automatic Harsh Shifting and Shudder
Occasional · medium severity
Typical onset: 30,000-70,000 mi
Symptoms: hard shift from 1st to 2nd gear, shudder or vibration during light acceleration, delayed engagement when shifting to drive, clunk into reverse
Fix: GM 8L45 transmission clutch pack issues and valve body wear. TSB 19-NA-206 covers updates, but many need valve body replacement or full rebuild. Fluid replacement with AC Delco fluid sometimes helps temporarily. Valve body R&R is 6-8 hours, rebuild 12-16 hours.
Estimated cost: $2,800-6,500
Rear Differential Bearing Whine
Occasional · low severity
Typical onset: 50,000-90,000 mi
Symptoms: whining or howling noise from rear that increases with speed, noise changes with throttle input, vibration through floor at highway speeds
Fix: Pinion bearing preload set incorrectly from factory or bearing wear on higher-mileage units. Requires differential teardown, bearing replacement, and gear pattern reset. 4-6 labor hours.
Estimated cost: $1,200-2,000
Fuel Injection System Failures (Diesel)
Occasional · high severity
Typical onset: 70,000-110,000 mi
Symptoms: hard starting when cold, rough idle with misfires, white smoke, fuel in oil (dilution), check engine light with injector codes
Fix: Duramax 2.8L injectors fail internally, allowing fuel into crankcase. Requires injector replacement (often all four preventively) plus oil and filter changes until fuel dilution clears. Each injector 1.5 hours, so all four is 6-7 hours with system priming.
Estimated cost: $3,500-5,200
Transfer Case Encoder Motor Failure (4WD Models)
Occasional · medium severity
Symptoms: service 4WD message on dash, unable to shift into or out of 4WD modes, grinding noise from transfer case area, 4WD indicator lights flashing
Fix: Encoder motor on front of transfer case fails, preventing mode shifts. Common issue across GM trucks with this drivetrain. Motor replacement is straightforward once transfer case is accessed. 2-3 labor hours.
Estimated cost: $600-950
Owner tips
Avoid the 2.8L Duramax diesel unless you can verify complete engine replacement history under warranty — this is not an exaggeration, the failure rate is that high
Check transmission fluid color and condition carefully on test drive; pink/red fluid is normal, brown or burnt smell means trouble ahead
3.6L V6 models are the reliability sweet spot for this generation — adequate power, proven engine architecture
Change differential fluid at 50k miles even though GM says lifetime fill — cheap insurance against bearing noise
On 4WD models, exercise the transfer case monthly even if you don't need 4WD to keep encoder motor and shift mechanism from seizing
Buy a V6 gas model with maintenance records and avoid the Duramax diesel entirely — the engine failure rate makes it a financial time bomb even at low used prices.
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.
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Every control module on the 2015-2026 Chevrolet Colorado — 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.
⚠️ 4G LTE from 2015+. Requires OnStar account and ESN programming. 2018+ SGW-locked.
Seat Control Module (SCM)0.8 hr R&Rrelearn only +0.2 hrwith power seats and memory function▸ programming details
📍 Under driver seat, mounted to seat frame
🔧 Self-calibration
⚠️ Controls seat position and memory. Self-calibration after replacement.
Headlamp Control Module (HCM)0.6 hr R&Rrelearn only +0.1 hrwith automatic headlamps or DRL▸ programming details
📍 Behind left headlamp assembly in engine compartment
🔧 Self-calibration
⚠️ Controls automatic headlamp operation and DRL. Basic models use BCM-integrated control.
Trailer Brake Control Module (TBCM)0.6 hr R&Rrelearn only +0.2 hrwith factory trailer brake controller▸ programming details
📍 Under instrument panel, left of steering column
🔧 Self-calibration via infotainment
⚠️ Integrated trailer brake controller. User calibration via touchscreen.
Rear Vision Camera Module (RVCM)0.5 hr R&Rrelearn only +0.1 hr▸ programming details
📍 Integrated with tailgate handle camera assembly
🔧 Self-calibration
⚠️ Standard equipment 2018+. Displays on infotainment screen. No programming typically required.
Tire Pressure Monitor Control Module (TPMS)relearn only +0.2 hr▸ programming details
📍 Integrated with BCM
🔧 TPMS relearn tool or GDS2/MDI
⚠️ Receives 315 MHz signals from wheel sensors. Sensor ID relearn required after tire service or sensor 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 Chevrolet Bolt EV and 2021 GMC Canyon and Sierra 1500, 2500 and 3500, Yukon, Yukon XL, Cadillac Escalade and Escalade ESV and Chevrolet Blazer, Camaro, Colorado, Equinox, Silverado 1500, 2500 and 3500, Suburban and Tahoe vehicles. Incorrect bolts may have been used at one or more fastening locations to secure the seat belts to the vehicle. If an incorrect bolt was used, the seat belt may not be properly attached to the vehicle.
Consequence: If a seat belt assembly is not properly attached to the vehicle, the seat belt may not properly restrain an occupant in the event of a crash, increasing the risk of injury.
Remedy: GM will notify owners, and dealers will replace the suspect bolts, free of charge. The recall began January 29, 2021. Owners may contact GMC customer service at 1-800-462-8785, Cadillac customer service at 1-800-458-8006, or Chevrolet customer service at 1-800-222-1020. GM's number for this recall is N202322230.
Performance
Horsepower
181hp
Torque
369lb-ft
0–60 mph
9.1sec
Quarter mile
16.8sec
Top speed
100mph
Fuel economy (EPA)
City
20mpg
Highway
30mpg
Combined
23mpg
Fuel
Diesel
Capability & size
Towing capacity
7,700lb
Payload
1,578lb
Curb weight
4,750lb
EPA class
Small Pickup Trucks 4WD
Wiper blades
Third generation (2015-2023). Pickup trucks do not have rear wipers.
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 Chevrolet Colorado 2.8L I4 Duramax Diesel 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.