Circuit/System Testing

Repair one of the following conditions with the camshaft timing drive components:

1. 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 Camshaft Timing Drive Chain Alignment Diagram and inspect the timing chain and sprockets for proper alignment.
2. The supply of clean pressurized engine oil to the CMP actuator 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 Camshaft Cleaning and Inspection .
   • 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.
3. Remove the engine front cover, refer to Engine Front Cover Disassemble and inspect the timing chain, tensioner, and sprockets for proper alignment, wear or damage. Refer to Camshaft Timing Drive Components Cleaning and Inspection .
   • If any parts are worn or damaged, replace as necessary.
   • If everything else tests normal, replace the CMP actuator.