Without Scan Tool

Diagnostic trouble codes (DTC) can he displayed by either using the Scan Tool or on-board diagnostics.

Displaying (DTC)s Using On-board Diagnostics
To displaying DTCs using on-board diagnostic method:
1. Press OFF and WARMER (digital IPC) or OFF and PASSENGER WARMER (analog IPC).
2. Press LO (fan speed) button until Air Conditioning Programmer (ACM)? appears.
3. Press HI (fan speed) ACM CODES? appears.
4. Press HI (fan speed). ACM DTC's appear.