For 1990-2009 cars only
- Check the engine oil level. Fill, as required.
- Using the scan tool, check for diagnostic codes within the engine control module (ECM). Refer to Diagnostic System Check - Vehicle in Vehicle DTC Information. Repair, as required.
- Verify proper engine oil pressure and operation of the displacement on demand (DoD) oil pressure relief valve. Refer to Oil Pressure Diagnosis and Testing .
- Verify proper operation of the DoD system components. Refer to Displacement on Demand (DoD) System Compression Test .
- Remove the valve lifter oil manifold (VLOM). Refer to Valve Lifter Oil Manifold Replacement .
- Verify proper operation of the VLOM. Refer to Displacement on Demand (DoD) Valve Lifter Oil Manifold Diagnosis and Testing .
- Replace the DoD valve lifters, as required. Both intake and exhaust lifters should be replaced in pairs. Refer to Valve Lifter Replacement .
