Reading and Clearing Diagnostic Trouble Codes

System Check:

System Check Cont.:

Symptom Table:

^ Diagnosis for the temperature control portion of this system is based on malfunction codes stored in the HVAC Control Assembly. When a code has been set, the C (or F) indicator will flash.

On-Board Diagnostic Mode
The C68 air conditioning is equipped with an on board diagnostic feature which allows the HVAC Control Assembly to detect certain system faults. The diagnostic feature can also be used to display certain data parameters. If the HVAC Control Assembly detects a fault in the system, the C (or F) indicator will flash during the first two minutes of vehicle operation.

Entry into the diagnostic mode is gained by depressing the "OUTS TEMP" and "BI-LEV" buttons at the same time. Once the diagnostic mode is entered, any trouble codes stored will be displayed. If none are present, 00 will be displayed.

If the "WARM" button is depressed after the trouble codes have been displayed, the data mode will be entered. The information available in the data mode is displayed in units used by the computer which may not be of use in observing the system. To exit the diagnostic mode, press any mode button.

Code Descriptions:

A list of Trouble Codes and their meanings are found in the above image.

Clearing Codes
To clear codes from the HVAC Control Assembly, remove ELEC Fuse.