Review the system operation in order to familiarize yourself with the system functions. As required, disable the auto-stop function prior to repair. Refer to Hybrid Modes of Operation Description.

Low oil pressure

1. Perform an oil pressure test. Refer to Oil Pressure Diagnosis and Testing.
2. Repair or replace components, as required.

Loose and/or worn valve rocker arm attachments

1. Inspect the valve rocker arm, bolt, and pedestal.
2. Repair or replace, as required.

Worn or damaged valve rocker arm

1. Inspect the rocker arm for wear or missing needle bearings
2. Replace the valve rocker arms, as required.

Bent or damaged push rod

Inspect the following components and replace, as required:

Inspect the top of the pistons for valve contact. If the top of the piston shows valve contact, replace the piston and pin assembly.

Improper lubrication to the valve rocker arms

Inspect the following components and repair or replace, as required:

Broken valve spring

Replace the valve spring and spring shim.

Worn or dirty valve lifters

Replace the valve lifters, as required.

Active fuel management valve lifter with a broken spring

Replace the valve lifters, as required.

Improper operation of the active fuel management oil pressure relief valve

Repair, as required. Refer to Cylinder Deactivation (Active Fuel Management) Oil Pressure Relief Valve Diagnosis and Testing.

Improper operation of the camshaft position (CMP) actuator and/or control system

Repair, as required. Refer to Camshaft Position Actuator and Solenoid Valve Diagnosis and Testing.

Stretched or broken timing chain and/or damaged sprocket teeth

Replace the timing chain, tensioner, sprocket, and camshaft position actuator.

Worn engine camshaft lobes

1. Inspect the engine camshaft lobes.
2. Replace the camshaft and valve lifters, as required.

Worn valve guides or valve stems

Inspect the following components and repair, as required:

Stuck valves

Carbon on the valve stem or valve seat may cause the valve to stay open.

Inspect the following components and repair, as required:

Cut or damaged oil pump screen O-ring seal which may cause aeration of the engine oil

Repair, as required. Refer to Oil Pressure Diagnosis and Testing.