Lifter Failure and Active Fuel Management Problems in Chevrolet and General Motors Vehicles

The 5.3L AFM (Active Fuel Management) system—also known as Displacement on Demand (DoD)—has been a common feature in Chevrolet and GM V8 engines, including the 5.3L V8 found in Silverado, Tahoe, Suburban, and other GM vehicles. While designed to improve fuel economy by deactivating half the engine’s cylinders under light load, the system has been plagued by notorious lifter failures that have led to widespread consumer complaints, technical service bulletins, and even lawsuits.

🔧 What is AFM / DoD and How Does it Work?

AFM allows the engine to switch between 8-cylinder and 4-cylinder mode by deactivating four of the engine's hydraulic lifters during light-load conditions (like highway cruising). This is done using special AFM lifters and solenoids controlled by the engine computer.

⚠️ The Lifters: A Common Failure Point

The lifters used in AFM engines are more complex and prone to failure than traditional hydraulic lifters. Common failure issues include:

  • Collapsed lifters: The AFM lifter can become stuck in the collapsed position, permanently disabling the affected cylinder.

  • Misfires and ticking noises: Often caused by the lifter not extending or retracting properly.

  • Bent pushrods or damaged cam lobes: A failed lifter can lead to mechanical damage in the valvetrain.

  • CEL / DTCs: Diagnostic codes like P0300 (random misfire) or cylinder-specific misfire codes (e.g., P0301) are common.

🚨 Known Affected Vehicles (not exhaustive)

  • Chevrolet Silverado 1500 (2007–2021 with 5.3L AFM engine)

  • Chevrolet Tahoe / Suburban

  • GMC Sierra 1500

  • GMC Yukon

  • Chevrolet Avalanche

  • Chevrolet Camaro (with 5.3L V8)

  • Other GM vehicles with AFM-equipped V8s

🧾 TSBs and Manufacturer Response

General Motors has issued Technical Service Bulletins (TSBs) acknowledging lifter issues and often recommends replacing the entire set of lifters and possibly the camshaft. However, in many cases, the underlying AFM design is the problem, meaning failures can reoccur—even after repair.

💰 Repair Costs

  • Lifter replacement: $2,500–$4,500+

  • Camshaft replacement: Often needed due to collateral damage

  • Engine replacement: In extreme cases

⚖️ Lemon Law and Legal Options (California)

If you’ve had repeated repairs for lifter failure, or your vehicle has been in the shop for over 30 days, you may have a valid claim under the California Lemon Law.

🔹 Remedies may include:

  • Repurchase or replacement of your vehicle

  • Cash compensation

  • Attorney’s fees paid by GM

🛑 Protect Your Rights Under California Lemon Law

If you are like many GM owners who are now experiencing serious engine issues with your Chevrolet, GMC, or Cadillac, you may be entitled to compensation under the California Lemon Law.

Compensation may include:

  • A complete repurchase of your defective vehicle

  • A replacement vehicle

  • Or substantial cash reimbursement for damage already caused by the defect

If you’re in California and your GM truck or SUV has a 5.3L engine, lifter, or transmission defect, call Valero Law, APC at (424) 299-4447 or complete our free Lemon Law case evaluation form today.

Joshua Valero