Diagnostic Procedure - Testing

Diagnosis of the CCC system should be performed in the following order:

Make sure that all engine systems not related to the CCC system are operating properly. Do not proceed with testing unless all other problems have been repaired.
Put the system into diagnostic mode and record trouble codes flashed by "CHECK ENGINE" light. Exit the diagnostic mode.
If trouble codes were displayed, decide whether the codes are "hard" or "intermittent" trouble codes.
Proceed to Diagnostic Circuit Check chart. Follow all instructions given in that chart.
If no trouble codes were displayed, proceed to Field Service Mode.
NOTE: The FIELD SERVICE MODE is an integral part of the DIAGNOSTIC CIRCUIT CHECK flow chart. Be sure to start at the beginning of the DIAGNOSTIC CIRCUIT CHECK to ensure that all problems have been diagnosed and repaired before proceeding to the FIELD SERVICE MODE part of the diagnostic chart.
If no trouble is indicted by any of these charts, use the TROUBLE SHOOTING material in the CCC TESTS W/O CODES article in this section. The comments there will send you to the proper component charts or tell you what to fix.
After any repairs are made, perform System Performance Check. Clear any trouble codes.

NOTE: Each of the steps listed here are described later in this section. If you are unsure of the proper way to test, read through the following material.