Operation CHARM: Car repair manuals for everyone.

Heating and Air Conditioning




Climate Control System

DTC Charts

NOTE: Network DTCs (U-codes) are often a result of intermittent concerns such as damaged wiring or low battery voltage occurrences. Additionally, vehicle repair procedures such as module reprogramming often set network DTCs. Replacing a module to resolve a network DTC is unlikely to resolve the concern. To prevent repeat network DTC concerns, inspect all network wiring, especially connectors. Test the vehicle battery, refer to Battery, Mounting and Cables Testing and Inspection.

Auxiliary Heater Control Module (AHCM) DTC Chart