Failure Code Determination

It is necessary to determine if a code is intermittent or if it is a "hard failure" code. Diagnostic charts cannot be used to analyze intermittent failures. To determine which are "hard failure" codes, proceed as follows:

1. Enter diagnostic mode, read and record trouble codes. Clear trouble codes and 'Exit' diagnostic mode. Turn ignition "ON" and wait 5 seconds. Start engine and accelerate to 2000 RPM for 5 seconds.
2. Return to idle and shift transmission to "Drive" position. Shift transmission to "Park" position. If "Check Engine" light comes on, enter diagnostic mode and read trouble codes. Only "hard failure" trouble codes will appear at this time.