Dual Automatic Temperature Control Module - Diagnostic Methods

The dual automatic temperature control 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.

On-demand DTCs can also be retrieved by carrying out the Dual Automatic Temperature Control Module Self-Test. To retrieve and/or clear continuous DTCs carry out the Dual Automatic Temperature Control Module - Retrieve Continuous DTCs procedure. Always carry out the Dual Automatic Temperature Control Module Self-Test before retrieving continuous DTCs. Dual Automatic Temp Control Module - Retrieve Continuous DTCs Dual Automatic Temperature Control Module Self-Test

If no DTCs are present, refer to the symptom chart for the appropriate diagnostic action. Symptom Related Diagnostic Procedures