Circuit/System Testing

With the ignition OFF, inspect the engine or review the service history of the vehicle for any recent repairs involving the timing chain, camshaft, or crankshaft.
- If recent repairs were made, refer to Timing Chain and Sprockets Replacement and inspect the timing chain and sprockets for proper alignment.
The supply of clean pressurized engine oil to the CMP actuator spool valve is critical to CMP actuator performance. Review the service history of the vehicle for extended intervals between oil changes. Inspect the engine oil for the following:
- Viscosity breakdown
- Incorrect viscosity or contains aftermarket additives
- Low level
- Debris or other contaminants
- Mixed with engine coolant
- Low pressure
- If the engine oil is old, burnt, contains additives, or is not the correct viscosity, change the oil and filter.
- If the engine oil level is low, refer to Oil Leak Diagnosis or Oil Consumption Diagnosis to determine the cause for the loss of oil, and repair as necessary.
- If the engine oil is contaminated or contains debris, determine the cause, and remove the timing chain, CMP actuator, and sprockets. Refer to Timing Chain and Sprockets Replacement . Remove the filter screen in the camshaft that supplies engine oil to the CMP actuator. Refer to Camshaft and Bearings Cleaning and Inspection . Inspect the screen and oil passages for debris. Replace the screen as necessary.
- If the engine oil is mixed with coolant, refer to Coolant in Engine Oil to determine the cause, and repair as necessary.
- If the engine oil pressure is low, refer to Oil Pressure Diagnosis and Testing to determine the cause, and repair as necessary.
Remove the engine front cover, refer to Engine Front Cover Replacement and inspect the timing chain, tensioner, and sprockets for wear or damage Refer to Timing Chain and Sprockets Cleaning and Inspection .
- If any parts are worn or damaged, replace as necessary.
- If everything else tests normal, replace the CMP actuator.