Cylinder Deactivation (Active Fuel Management) System Diagnosis

Cylinder Deactivation (Active Fuel Management) System Diagnosis


Important: Cylinder Deactivation (Active Fuel Management) System Diagnosis is applicable for RPO LH6/LMG/LY5/LC9/L76.


1. Measure the engine oil level. Fill, as required.
2. Using the scan tool, inspect for diagnostic codes within the engine control module (ECM). Refer to Diagnostic System Check - Vehicle . Repair, as required.
3. Verify proper engine oil pressure and operation of the active fuel management oil pressure relief valve. Refer to Oil Pressure Diagnosis and Testing (Component Tests and General Diagnostics) .
4. Verify proper operation of the active fuel management system components. Refer to Cylinder Deactivation (Active Fuel Management) System Compression Test (Component Tests and General Diagnostics) .
5. Remove the valve lifter oil manifold. Refer to Valve Lifter Oil Manifold Replacement (Valve Lifter Oil Manifold Replacement) .
6. Verify proper operation of the valve lifter oil manifold. Refer to Cylinder Deactivation (Active Fuel Management) Valve Lifter Oil Manifold Diagnosis and Testing (Component Tests and General Diagnostics) .
7. Replace the active fuel management valve lifters, as required. Both intake and exhaust lifters should be replaced in pairs. Refer to Valve Lifter Replacement (L92 - First Design) (Valve Lifter Replacement (L92 - First Design))Valve Lifter Replacement (L92 - Second Design) (Valve Lifter Replacement (L92 - Second Design))Valve Lifter Replacement (LY2 and LY6) (Valve Lifter Replacement (LY2 and LY6))Valve Lifter Replacement (LH6, LMG, LY5 and L76) (Valve Lifter Replacement (LH6, LMG, LY5 and L76)) .