Begin the system diagnosis by reviewing the Disassembled Views, Engine Component Description, Lubrication Description, Drive Belt System Description and Cylinder Deactivation (Active Fuel Management) Oil Pressure Relief Valve Diagnosis and Testing. Reviewing the description and operation information will help you determine the correct symptom diagnostic procedure when a malfunction exists. Reviewing the description and operation information will also help you determine if the condition described by the customer is normal operation. Refer to Symptoms - Engine Mechanical, in order to identify the correct procedure for diagnosing the system and where the procedure is located.