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GMC · Known Issues

2021 GMC Sierra 1500 Problems: 8 Known Issues

2021 model year · 3,286+ owner reports · Updated September 2026

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Issue summary

According to Au7o's analysis of 3,286+ owner reports, the 2021 GMC Sierra 1500 has 8 documented known issues, with 4 rated critical. The most serious are AFM/DFM Lifter Collapse and Failure ($4,000-$8,000 repair), 8-Speed/10-Speed Transmission Torque Converter Shudder ($150-$4,500 repair), Electronic Brake Control Module Failure ($150-$1,500 repair) and P0016 — Crank/Cam Correlation Fault from Stretched Timing Chain on 5.3L AFM V8 ($150-$1,800 repair). The most commonly reported issue is AFM/DFM Lifter Collapse and Failure with 1,250 owner reports. Across all issues with published estimates, repair costs range from $20 to $8,000. DIY maintenance guides at au7o.io.

In This Article

  • Sierra 1500 Engine4
  • Sierra 1500 Transmission1
  • Sierra 1500 Brakes1
  • Sierra 1500 Electrical1
  • Sierra 1500 Emissions1
  • Recalls22
  • FAQ
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In This Article

  • Engine4
  • Transmission1
  • Brakes1
  • Electrical1
Emissions
1
  • Recalls22
  • FAQ
  • All 8 Known Issues

    Filter:
    ALL YEARS2026202520242023202220212020201920182017201620152014201320122011201020092008200720062005200420032002200120001999
    Community reported
    1,250 owners

    On the 2014-2023 GMC Sierra 1500, the Active Fuel Management (AFM) and Dynamic Fuel Management (DFM) systems use special hydraulic lifters that collapse to deactivate cylinders for fuel economy. These lifters are prone to premature failure due to poor physical design and inadequate oil flow. Failures can occur as early as 4-digit mileage on newer trucks or 50,000-100,000 miles on older models. When a lifter fails, it can cause catastrophic engine damage requiring complete engine teardown.

    This issue also affects: Buick LeSabre, Buick Park Avenue, Buick Cascada

    Common Symptoms

    • Engine misfires or rough idle
    • Check engine light with cylinder misfire codes
    • Ticking or knocking noise from engine
    • Reduced engine power
    • Metal shavings in oil
    • Engine vibration during cylinder deactivation

    How to Fix

    Replace all 16 lifters and associated components (camshaft inspection recommended). Install AFM/DFM delete kit to disable cylinder deactivation permanently. Use AFM/DFM disabler device to prevent system activation. Use high-quality synthetic oil and change at 5,000 mile intervals.

    Typical repair cost:$4,000 - $8,000

    Research This Issue

    Based on 1,250 owner reports

    GoogleRedditYouTubeNHTSA
    Community Reported
    High Confidence1,250 owner reportsLast reported by owners Feb 2024Reviewed Feb 2026

    On the 2007-2021 GMC Sierra 1500, p0016 means the crankshaft and Bank 1 intake camshaft are out of sync beyond tolerance. On the 5.3L V8 Sierra 1500 this is a signature failure because of two engine-specific problems: (1) the timing chain stretches over time — accelerated by AFM lifter debris and extended oil-change intervals — retarding cam timing until correlation exceeds threshold; and (2) the cam actuator (VVT) solenoid or phaser sticks. The AFM V8s are also known for oil consumption, and low/dirty oil starves the phasers and clogs solenoid screens, which both triggers P0016 and worsens chain wear. This is more serious than the related P0011: a severely stretched chain can jump a tooth and cause piston-to-valve contact, so continued driving is risky.

    This issue also affects: Buick Cascada, Buick Enclave, Buick Encore

    Common Symptoms

    • Check engine light
    • Rough idle
    • Rattle from front of engine on cold start
    • Reduced power / poor fuel economy
    • Hard start or stalling in severe cases

    How to Fix

    Check oil level/condition first — low or sludged oil alone can set it. Use a scan tool to read cam-retard/phaser data. If the timing chain is stretched (confirmed by measuring cam retard or valve-cover inspection), replace the timing chain, guides, tensioner, and cam phaser/sprocket; if only the VVT solenoid is stuck, replace it. Address AFM oil consumption to prevent recurrence.

    What you need to diagnose it

    The repair instructions explicitly call for reading stored codes. Use a scanner that can read the named code families before choosing a repair.The recommended scanner supports these code families; confirm your exact year, model and module coverage before buying.

    • ANCEL AD310 Classic OBD-II Scanner

      Read & clear engine (P) codes

      $20–$40View

    As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.

    Reading and clearing the code is DIY work. Module replacement or reprogramming is not — most modules are VIN-programmed, so a new one does nothing until a shop codes it to your car. Check for an open recall or service bulletin before buying anything.

    Typical repair cost:$150 - $1,800

    Research This Issue

    GoogleRedditYouTubeNHTSA
    Community Reported
    High ConfidenceVerifiedReviewed Jul 2026
    Community reported
    345 owners

    On the 2014-2023 GMC Sierra 1500, direct injection engines do not spray fuel over the intake valves like port injection systems, allowing carbon deposits from oil and blow-by gases via the PCV system to accumulate on intake valve backs and ports. Over time, this buildup restricts airflow causing performance and efficiency loss. The 5.3L and 6.2L engines with direct injection are susceptible to this issue typically after 60,000-100,000 miles.

    This issue also affects: Buick LeSabre, Buick Park Avenue, Buick Cascada

    Common Symptoms

    • Reduced fuel economy
    • Rough idle
    • Hesitation during acceleration
    • Engine misfires
    • Reduced power output
    • In severe cases, engine knock or pinging

    How to Fix

    Walnut shell blasting of intake valves (professional service). Chemical intake cleaning treatment. Install oil catch can to reduce PCV contamination. Manual intake manifold removal and valve cleaning.

    Typical repair cost:$400 - $800

    Research This Issue

    Based on 345 owner reports

    GoogleRedditYouTubeNHTSA
    Community Reported
    Medium Confidence345 owner reportsLast reported by owners Feb 2024Reviewed Feb 2026

    On the 2007-2022 GMC Sierra 1500, p0011 means the Bank 1 intake camshaft is timed more advanced than the ECM commanded — the phaser is stuck/biased advanced. On the Sierra 1500 5.3L/6.2L, the dominant cause is a VVT (camshaft actuator) solenoid whose internal screen has clogged with oil sludge or AFM debris, jamming the plunger so oil pressure to the phaser can't be modulated. GM acknowledges sticking/binding solenoids in PIs such as PIP5130K and PIP5855. Low or incorrect-viscosity oil is a very common trigger, so oil condition is always checked first. Because AFM lifter wear sheds metal into the oil, that debris circulates and clogs the solenoid screens — tying P0011 directly to the trucks' oil-consumption reputation. Drivers report rough running, and in worse cases stalling when slowing to a stop.

    This issue also affects: Cadillac XT5, Chevrolet Avalanche, Chevrolet Equinox

    Common Symptoms

    • Check engine light
    • Rough idle / rough running
    • Stalling when slowing to a stop
    • Hard start
    • Reduced power and fuel economy

    How to Fix

    Check engine oil level, viscosity, and condition first; an oil/filter change with correct-spec oil sometimes clears it. A proven test is swapping the Bank 1 intake solenoid with another solenoid — if the code follows to P0014/P0021, the solenoid is bad. Replace the VVT/cam actuator solenoid (roughly $40-$90 part). If the phaser or timing chain is worn, the timing set must be replaced.

    Typical repair cost:$40 - $450

    Research This Issue

    GoogleRedditYouTubeNHTSA
    Community Reported
    High ConfidenceVerifiedReviewed Jul 2026
    Community reported
    890 owners

    On the 2015-2023 GMC Sierra 1500, the 8L90 8-speed and 10L80/10L90 10-speed automatic transmissions experience shuddering during light throttle acceleration, particularly at highway speeds between 35-60 mph. The issue is caused by the torque converter lock-up clutch slipping and chattering. Harsh shifts between gears, especially 1st to 2nd and 2nd to 1st, are also commonly reported.

    This issue also affects: Buick Encore GX, Buick Regal, Cadillac DeVille

    Common Symptoms

    • Vibration or shudder during light acceleration at 35-60 mph
    • Harsh or jerky shifts between gears
    • Transmission slipping sensation
    • Shudder when torque converter locks up
    • Intermittent transmission hesitation

    How to Fix

    Transmission fluid flush with updated Mobil 1 Synthetic LV ATF HP fluid (GM part number 19417577). Torque converter replacement. Transmission control module software update. Complete transmission replacement in severe cases.

    Typical repair cost:$150 - $4,500

    Research This Issue

    Based on 890 owner reports

    GoogleRedditYouTubeNHTSA
    Community Reported
    High Confidence890 owner reportsLast reported by owners Feb 2024Reviewed Feb 2026
    Community reported
    345 owners

    On the 2014-2023 GMC Sierra 1500, the electronic brake control module (EBCM) experiences failures causing ABS, traction control, and stability control systems to malfunction. Issues range from warning lights illuminating to complete system failures. The 2023 models have a specific recall for software that may fail to display a warning light when brake fluid loss occurs.

    This issue also affects: Chevrolet Avalanche, Chevrolet Blazer, Chevrolet Colorado

    Common Symptoms

    • ABS warning light illuminated
    • Traction control and stability control warning lights
    • Service Brake Assist message on dash
    • ABS system activates unexpectedly or not at all
    • Brake pedal feels different or spongy
    • Multiple warning lights illuminate simultaneously

    How to Fix

    EBCM software reprogramming at dealer. EBCM replacement. Wheel speed sensor replacement if sensor-related. Check and repair wiring connections.

    Typical repair cost:$150 - $1,500

    Research This Issue

    Based on 345 owner reports

    GoogleRedditYouTubeNHTSA
    Community Reported
    Medium Confidence345 owner reportsLast reported by owners Feb 2024Reviewed Feb 2026
    Community reported
    456 owners

    On the 2019-2023 GMC Sierra 1500, the infotainment system experiences intermittent complete audio loss affecting stereo, turn signals, and safety warning sounds. The audio system may randomly go to maximum volume and cannot be controlled. OTA software updates have caused additional issues including erratic blinker tones, constant reboots while driving, and frozen camera screens.

    This issue also affects: Chevrolet Equinox, Chevrolet Silverado 1500

    Common Symptoms

    • Complete loss of all interior audio for hours
    • Radio randomly goes to maximum volume
    • Turn signal and safety warning sounds stop working
    • Infotainment screen freezes or reboots while driving
    • Backup camera display freezes or goes black
    • Bluetooth connectivity issues

    How to Fix

    Perform hard reset by disconnecting battery for 30 minutes. Software update at dealership. Replace infotainment head unit/radio module. Replace audio amplifier for Bose systems.

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    Typical repair cost:$0 - $2,500

    Research This Issue

    Based on 456 owner reports

    GoogleRedditYouTubeNHTSA
    Community Reported
    Medium Confidence456 owner reportsLast reported by owners Feb 2024Reviewed Feb 2026

    On the 2007-2023 GMC Sierra 1500, p0455 indicates a large (gross) EVAP leak — the ECM cannot pull or hold vacuum in the evaporative system at all. On the Sierra 1500 the classic causes are a completely missing/unsealed gas cap, a stuck-open or failed EVAP vent solenoid (mounted under the truck near the fuel tank/spare tire, where it's exposed to road spray, dirt, and corrosion), and a cracked or disconnected vapor/vent hose. Because the vent solenoid sits at the canister under the bed, water intrusion and corrosion cause it to stick open, which the ECM reads as a wide-open system; a tell-tale symptom is the fuel nozzle repeatedly clicking off during refueling. The filler vent hose connector fracture noted in GM literature can also escalate to P0455. Symptom-wise the driver usually sees only the CEL, sometimes a fuel smell, and no performance loss.

    This issue also affects: Chevrolet Corvette, Chevrolet Express, Chevrolet Silverado 1500

    Common Symptoms

    • Check engine light
    • Fuel vapor smell
    • Missing or loose gas cap
    • Fuel nozzle clicks off repeatedly when refueling
    • Fails emissions test

    How to Fix

    Confirm the gas cap is present and sealing. Smoke-test the EVAP system to find the large leak. The most common repair on these trucks is replacing the under-body EVAP vent solenoid/valve at the canister; also inspect and replace cracked vapor lines and the fuel filler vent hose. Clear codes and run the EVAP monitor to confirm.

    Typical repair cost:$20 - $350

    Research This Issue

    GoogleRedditYouTubeNHTSA
    Community Reported
    High ConfidenceVerifiedReviewed Jul 2026
    NHTSA Recalls22 recalls

    TIRES

    General Motors LLC (GM) is recalling certain 2020 Buick Enclave, Cadillac XT4, XT5, Escalade, Escalade ESV, Chevrolet Suburban, Tahoe, Traverse, GMC Yukon, Yukon XL, 2018-2021 Chevrolet Express, GMC Savana, 2019-2020 Chevrolet Blazer, Silverado 1500, GMC Acadia, Sierra 1500, and certain Continental tires sold to the aftermarket for various model year 2018-2021 vehicles. The affected tires were cured for too long during production.

    Campaign #21V11500025/02/2021

    SERVICE BRAKES, HYDRAULIC:ANTILOCK/TRACTION CONTROL/ELECTRONIC LIMITED SLIP:ABS WARNING LIGHT

    General Motors LLC (GM) is recalling certain 2019 Chevrolet Silverado 1500, Cadillac CT6, and GMC Sierra 1500 vehicles. Due to an Electronic Brake Control Module (EBCM) software error, the vehicle's Electronic Stability Control (ESC) and Antilock Brake System (ABS) may become disabled. Furthermore, if this specific error occurs, the vehicle's diagnostics will not illuminate the instrument cluster ESC and ABS malfunction warning lights. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 126, "Electronic Stability Control" and 135, "Light Vehicle Brake Systems."

    Campaign #19V88900012/12/2019

    ELECTRICAL SYSTEM:12V/24V/48V BATTERY:CABLES

    General Motors LLC (GM) is recalling certain 2019-2020 Chevrolet Silverado 1500 and GMC Sierra 1500 trucks. The battery positive (B+) cable rings may have been manufactured with excessive glue, potentially causing an intermittent electrical connection between the B+ cable and alternator.

    Campaign #19V88800012/12/2019

    SEAT BELTS

    General Motors, LLC (GM) is recalling certain 2019-2021 Chevrolet Silverado 1500 and GMC Sierra 1500, 2021 Chevrolet Suburban and Tahoe and GMC Yukon XL and 2020-2021 Chevrolet Silverado 2500 and 3500 and GMC Sierra 2500 and 3500 vehicles. The seat belt brackets may not be secured to the seat frame in the front-row center seating position.

    Campaign #20V79200017/12/2020

    SERVICE BRAKES, HYDRAULIC:POWER ASSIST

    General Motors LLC (GM) is recalling certain 2019 Chevrolet Silverado 1500 and GMC Sierra 1500 vehicles. These vehicles received updated software for the Electronic Brake Control Module (EBCM). This software has an error, and as a result, the vehicle's electronic brake assist may be disabled. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 126, "Electronic Stability Control" and 135, "Light Vehicle Brake Systems."

    Campaign #20V05500030/01/2020

    + 17 more recalls. Check all on NHTSA.gov

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    Other GMC Models

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    Frequently Asked Questions

    What are the most common GMC Sierra 1500 problems?

    According to Au7o's analysis of 3,286+ owner reports, the 2021 GMC Sierra 1500 has 8 documented issues. The most frequently reported are: AFM/DFM Lifter Collapse and Failure, 8-Speed/10-Speed Transmission Torque Converter Shudder, Electronic Brake Control Module Failure. Of these, 4 are rated critical and should be addressed promptly.

    Is the GMC Sierra 1500 reliable?

    The 2021 GMC Sierra 1500 has 8 known issues documented across 3,286+ owner reports. 4 issues are rated critical: AFM/DFM Lifter Collapse and Failure and 8-Speed/10-Speed Transmission Torque Converter Shudder and Electronic Brake Control Module Failure and P0016 — Crank/Cam Correlation Fault from Stretched Timing Chain on 5.3L AFM V8. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

    How much does it cost to fix common GMC Sierra 1500 problems?

    Repair costs for known GMC Sierra 1500 issues range from $0 to $8,000, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, AFM/DFM Lifter Collapse and Failure, typically costs $4,000-$8,000 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

    What is the 2014-2023 GMC Sierra 1500 AFM/DFM Lifter Collapse and Failure?

    The Active Fuel Management (AFM) and Dynamic Fuel Management (DFM) systems use special hydraulic lifters that collapse to deactivate cylinders for fuel economy. These lifters are prone to premature failure due to poor physical design and inadequate oil flow. Failures can occur as… Repairs typically run $4,000-$8,000. Severity: high.

    What is the 2015-2023 GMC Sierra 1500 8-Speed/10-Speed Transmission Torque Converter Shudder?

    The 8L90 8-speed and 10L80/10L90 10-speed automatic transmissions experience shuddering during light throttle acceleration, particularly at highway speeds between 35-60 mph. The issue is caused by the torque converter lock-up clutch slipping and chattering. Harsh shifts between g… Repairs typically run $150-$4,500. Severity: high.

    What is the 2014-2023 GMC Sierra 1500 Electronic Brake Control Module Failure?

    The electronic brake control module (EBCM) experiences failures causing ABS, traction control, and stability control systems to malfunction. Issues range from warning lights illuminating to complete system failures. The 2023 models have a specific recall for software that may fai… Repairs typically run $150-$1,500. Severity: high.

    What is the 2007-2021 GMC Sierra 1500 P0016 — Crank/Cam Correlation Fault from Stretched Timing Chain on 5.3L AFM V8?

    P0016 means the crankshaft and Bank 1 intake camshaft are out of sync beyond tolerance. On the 5.3L V8 Sierra 1500 this is a signature failure because of two engine-specific problems: (1) the timing chain stretches over time — accelerated by AFM lifter debris and extended oil-cha… Repairs typically run $150-$1,800. Severity: high.

    What is the 2019-2023 GMC Sierra 1500 Infotainment System Audio Loss and Malfunction?

    The infotainment system experiences intermittent complete audio loss affecting stereo, turn signals, and safety warning sounds. The audio system may randomly go to maximum volume and cannot be controlled. OTA software updates have caused additional issues including erratic blinke… Repairs typically run $0-$2,500. Severity: medium.

    What is the 2014-2023 GMC Sierra 1500 Direct Injection Carbon Buildup on Intake Valves?

    Direct injection engines do not spray fuel over the intake valves like port injection systems, allowing carbon deposits from oil and blow-by gases via the PCV system to accumulate on intake valve backs and ports. Over time, this buildup restricts airflow causing performance and e… Repairs typically run $400-$800. Severity: medium.

    What is the 2007-2022 GMC Sierra 1500 P0011 — Intake Cam Over-Advanced from Sludge-Clogged VVT Solenoid on 5.3L V8?

    P0011 means the Bank 1 intake camshaft is timed more advanced than the ECM commanded — the phaser is stuck/biased advanced. On the Sierra 1500 5.3L/6.2L, the dominant cause is a VVT (camshaft actuator) solenoid whose internal screen has clogged with oil sludge or AFM debris, jamm… Repairs typically run $40-$450. Severity: medium.

    What is the 2007-2023 GMC Sierra 1500 P0455 — Gross EVAP Leak from Failed Vent Solenoid, Missing Gas Cap, or Broken Vent Hose?

    P0455 indicates a large (gross) EVAP leak — the ECM cannot pull or hold vacuum in the evaporative system at all. On the Sierra 1500 the classic causes are a completely missing/unsealed gas cap, a stuck-open or failed EVAP vent solenoid (mounted under the truck near the fuel tank/… Repairs typically run $20-$350. Severity: low.

    Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.

    Data sourced from 3,286+ owner reports, NHTSA recalls, TSBs, and automotive forums.