Alternate Diagnostic Methods - HVAC Module - Dual Automatic Temperature Control

Climate Control System

Alternate Diagnostic Methods - HVAC Module - Dual Automatic Temperature Control (DATC)

The DATC 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 HVAC Module - Dual Automatic Temperature Control (DATC) On-Demand Self Test. To retrieve and/or clear continuous DTCs carry out the HVAC Module - Dual Automatic Temperature Control (DATC) - Retrieve Continuous DTCs procedure. Always retrieve both on-demand and continuous DTCs before proceeding with diagnosis and/or repair.

If no DTCs are present, go to the GO to Symptom Chart - Climate Control Systems or GO to Symptom Chart - NVH for the appropriate diagnostic action. Symptom Chart - Climate Control Systems Symptom Chart - NVH

HVAC Module - Dual Automatic Temperature Control (DATC) On-Demand Self-Test

The HVAC Module - Dual Automatic Temperature Control (DATC) On-Demand Self-Test will retrieve on-demand (hard fault) DTCs only, it will not retrieve continuous DTCs. Continuous DTCs can be cleared when exiting the HVAC Module - Dual Automatic Temperature Control (DATC) On-Demand Self-Test. Make sure to retrieve continuous DTCs by carrying out the HVAC Module - Dual Automatic Temperature Control (DATC) - Retrieve Continuous DTCs procedure before clearing any DTCs.

- The HVAC Module - Dual Automatic Temperature Control (DATC) On-Demand Self-Test will not detect concerns associated with data link messages like engine coolant temperature or vehicle speed signals. A scan tool must be used to retrieve these concerns.
- The HVAC Module - Dual Automatic Temperature Control (DATC) On-Demand Self-Test will detect concerns in the system control functions and will display on-demand (hard fault) DTCs for concerns that are present during the self-test. The vehicle interior temperature should be between 4°-38°C (40°-100°F) when performing the self-test. If the temperatures are not within the specified ranges, false DTCs may be displayed.
- The self-test can be initiated after cycling the ignition switch from OFF to ON. Normal operation of the climate control system stops when the self-test is activated.
- To enter the self-test, press the OFF and DEFROST buttons simultaneously and release, then press the AUTO button within 2 seconds. The display will show a flashing blower icon for 20 seconds, after which all vacuum fluorescent segments will be displayed if there are no on-demand DTCs present. If DTCs are present the HVAC module - DATC will display "00 00" and then on-demand DTCs. Record all DTCs displayed.
- If any DTCs appear during the self-test, carry out the diagnostic procedure. Refer to the HVAC Module - Dual Automatic Temperature Control (DATC) DTC Chart and follow the ACTION for each DTC given. HVAC Module - Dual Automatic Temperature Control (DATC) DTC Chart
- To exit the self-test and retain all continuous DTCs, press any button except DEFROST. The HVAC module - DATC will exit the self-test and retain all DTCs.
- Always exit the self-test before powering the system down (system turned OFF). Once the self-test is exited the ignition switch must remain ON for at least 30 seconds to allow the temperature blend door actuators to automatically recalibrate.
- If a condition exists but no DTCs appear during the self-test, go to the GO to Symptom Chart - Climate Control Systems or GO to Symptom Chart - NVH. Symptom Chart - Climate Control Systems Symptom Chart - NVH

HVAC Module - Dual Automatic Temperature Control (DATC) - Retrieve Continuous DTCs

The HVAC module - DATC will retrieve only continuous (intermittent) DTCs when carrying out this procedure.

- Retrieval of continuous DTCs can be initiated after cycling the ignition switch from OFF to ON. Normal operation of the climate control system stops when retrieving continuous DTCs.
- To retrieve continuous DTCs, press the OFF and PANEL buttons simultaneously and release, then press the AUTO button within 2 seconds. All vacuum fluorescent segments will be displayed if there are no continuous DTCs present. Continuous DTCs are indicated by the presence of the degrees Celsius symbol (°C) on the HVAC module - DATC display. Record all DTCs displayed.

- NOTE: If continuous DTCs appear but the same DTC(s) do not appear during an on-demand self test, the fault may be intermittent in nature. Diagnosis should be conducted accordingly.

If any DTCs appear, carry out the diagnostic procedure. Refer to the HVAC Module - Dual Automatic Temperature Control (DATC) DTC Chart and follow the ACTION for each DTC given. HVAC Module - Dual Automatic Temperature Control (DATC) DTC Chart
- If a condition exists but no DTCs appear, go to the GO to Symptom Chart - Climate Control Systems or GO to Symptom Chart - NVH. Symptom Chart - Climate Control Systems Symptom Chart - NVH
- To exit and retain all continuous DTCs, press any button except DEFROST. The HVAC module - DATC will exit the retrieve continuous DTCs mode and retain all continuous DTCs.
- To exit and clear all continuous DTCs, press the DEFROST button. The HVAC module - DATC will exit the retrieve continuous DTCs mode and all continuous DTCs will be cleared.
- Always exit the procedure before powering the system down (system turned OFF). Once the procedure is exited the ignition switch must remain ON for at least 30 seconds to allow the temperature blend door actuators to automatically recalibrate.
- Continuous DTCs will be deleted after 80 ignition switch ON cycles after the intermittent fault occurs.

HVAC Module - Dual Automatic Temperature Control (DATC) Cold Boot Process

The purpose of the cold boot process is to allow the HVAC module - DATC to re-initialize and calibrate the actuators. To carry out the cold boot process, follow the steps below.

1. Turn the ignition switch to the OFF position.

2. Disconnect the HVAC module - DATC electrical connectors.

3. Wait one minute.

4. Connect the HVAC module - DATC electrical connectors.

5. Turn the ignition switch to the ON position.

6. Select any position except OFF on the HVAC module - DATC.

The HVAC module - DATC will now initialize and calibrate the actuators. Calibration of the actuators will take approximately 30 seconds.