Displaying & Reading Trouble Codes

The C68 Electronic Climate Control System is equipped with an on-board diagnostic feature which allows the Heater And A/C Control Assembly to detect certain system faults. The diagnostic feature is also used to display data parameters. If the Heater And A/C Control Assembly detects. a fault in the system, the C ° or F ° annunciator will flash during the first two minutes of vehicle operation.

To Enter the Diagnostic Mode:

1. Press the "OUTS TEMP" button then press the "BI-LEVEL" button. Hold both buttons for three seconds. -00 will be displayed, indicating entry to the diagnostic mode.

2. -00 is also called a diagnostic pointer. A diagnostic pointer indicates the parameter which can be displayed (see list below). To move through the list, press "FAN" button.

To display the information in a diagnostic pointer, press the "OUTS TEMP" button.

3. Diagnostic pointers -40-41 and -42 are output commands which allow you to control the position of the Air Mix Valve, the program number or the air delivery mode. To enter an output command, press the "OUTS TEMP" button when the desired pointer number is displayed, then use the "COOL" and "WARM" buttons to change the commanded value.

4. To exit the diagnostic mode, press the "OFF" button. To exit from a diagnostic pointer, but not from the diagnostic mode, press the fan button.