Important: Camshaft Position (CMP) Actuator and Solenoid Valve Diagnosis and Testing is applicable for RPO LY6/L76/L9H.
- Measure the engine oil level. Fill, as required.
 
- Using the scan tool, inspect for diagnostic codes within the engine control module (ECM). Refer to 
Diagnostic System Check - Vehicle. Repair, as required.
 
- Verify proper engine oil pressure and operation of the active fuel management oil pressure relief valve. Refer to 
Oil Pressure Diagnosis and Testing.
 
- Inspect the CMP actuator solenoid valve for proper operation. Refer to 
Camshaft Position Actuator Solenoid Valve Inspection.
 
| •  | If valve inspection confirms proper movement of the spool, replace the CMP actuator and CMP valve. | 
 
| •  | If valve inspection confirms improper movement of the spool, replace only the CMP valve. | 
 
- Verify proper operation of the CMP actuator control system. Refer to 
Diagnostic Starting Point - Engine Controls.