HVAC Module - Diagnostic Methods

HVAC MODULE - DIAGNOSTIC METHODS

The HVAC system must be diagnosed by first retrieving any DTCs, if present.
- An on-demand (hard fault) DTC indicates that the fault is currently present. An on-demand DTC suggests a wiring fault, disconnected connector or component failure.
- A continuous (intermittent) DTC alone (corresponding on-demand DTC is not present) indicates that the fault is an intermittent condition and may not be currently present. A continuous only DTC suggests a poor wiring connection, loose pin or terminal or intermittent component failure.

On-demand (hard fault) or continuous (intermittent fault) DTCs can be retrieved using a scan tool. If using a scan tool, refer to the scan tool operating manual.

Always retrieve both on-demand and continuous DTCs before proceeding with diagnosis and/or repair. If no on-demand or continuous DTCs are present, GO to Symptom Chart - Climate Control Systems for the appropriate diagnostic action. Symptom Chart - Climate Control System