Initial Inspection and Diagnostic Overview
INSPECTION AND VERIFICATION1. Verify the customer's concern by operating the climate control system to duplicate the condition.
Visual Inspection Chart:
2. Inspect to determine if one of the mechanical or electrical concerns apply.
3. As pinpoint tests and measurements are being carried out, be sure to inspect for any disconnected, loose-fitting or incorrectly installed component, module and in-line electrical connectors and pins.
4. If the inspection reveals obvious concerns that can be readily identified, repair as necessary.
5. If the concern remains after the inspection, connect the diagnostic tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the diagnostic tool menu. If the vehicle selection cannot be entered:
- check that the program card is correctly installed.
- check the connections to the vehicle.
- check the ignition switch position.
- check that the battery voltage is greater than 9V.
If the diagnostic tool still does not allow the vehicle selection to be entered, refer to the diagnostic tool manual.
6. CARRY OUT the Data Link Diagnostic Test using the diagnostic tool. If the diagnostic tool responds with:
- SCP+, SCP-, CAN or UBP circuits fault = ALL MODULE NO RESPONSE/NOT EQUIPPED, go to Module Communication Network Diagnostics to diagnose the network concern.
- If the powertrain control module (PCM) is not listed for a communication concern, turn the A/C controls to OFF and execute the self-test diagnostics for the PCM.
- If the EATC module is not listed for a communication concern, execute the self-test diagnostics for the EATC module.
7. If any PCM or EATC DTCs are retrieved, and are related to the concern, go to the Powertrain Control Module Diagnostic Trouble Code (DTC) Index or the Dual Automatic Temperature Control (EATC) Module Diagnostic Trouble Code (DTC) Index to continue the diagnostics. Diagnostic Trouble Code Tests and Associated Procedures
8. If no DTCs related to the concern are retrieved, GO to Symptom Chart to continue the diagnostics. Symptom Related Diagnostic Procedures
9. If the EATC module cannot be accessed by the diagnostic tool, GO to Pinpoint Test E. Test E: Incorrect/Erratic Direction of Airflow From Outlet(s)
Electronic Automatic Temperature Control Module - Diagnostic Methods
The electronic automatic temperature control (EATC) 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 diagnostic tool. If using a diagnostic tool, refer to the diagnostic tool operating manual.
On-demand DTCs can also be retrieved by carrying out the Electronic Automatic Temperature Control Module On-Demand Self Test. To retrieve and/or clear continuous DTCs, carry out the Electronic Automatic Temperature Control Module - Retrieve Continuous DTCs procedure. Always carry out the Electronic Automatic Temperature Control Module On-Demand Self Test before retrieving continuous DTCs.
If no DTCs are present, GO to Symptom Chart for the appropriate diagnostic action. Symptom Related Diagnostic Procedures
EATC Module On-Demand Self Test
The EATC Module 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 EATC Module On-Demand Self Test. Make sure to retrieve continuous DTCs by carrying out the Electronic Automatic Temperature Control Module - Retrieve Continuous DTCs procedure before clearing any continuous DTCs.
- The EATC Module On-Demand Self Test will not detect concerns associated with data link messages like engine coolant temperature or vehicle speed signals. A diagnostic tool must be used to retrieve these concerns.
- The EATC Module 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°C-38°C (40°F-100°F) when carrying out 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 EATC module 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 Electronic Automatic Temperature Control Module Diagnostic Trouble Code Index and follow the ACTION for each DTC given. Diagnostic Trouble Code Tests and Associated Procedures
- If a condition exists, but no DTCs appear during the self-test, GO to Symptom Chart Condition: The EATC System Is Inoperative, Intermittent or Incorrect Operation. Symptom Related Diagnostic Procedures
- To exit the self-test and retain all DTCs, press any button except DEFROST. The EATC module will exit the self-test and retain all DTCs.
- To exit the self-test and clear all DTCs, press the DEFROST button. The EATC module will exit the self-test and all DTCs will be cleared.
- 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 door actuators to automatically recalibrate.
- Continuous DTCs will be deleted after 80 ignition switch ON cycles after the intermittent fault occurs.
EATC Module - Retrieve Continuous DTCs
The EATC module 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 DEFROST buttons simultaneously and release, then press the RECIRC 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 Celsius symbol (°C) on the EATC module display. Record all DTCs displayed.
- If any DTCs appear, carry out the diagnostic procedure. Refer to the Electronic Automatic Temperature Control Module Diagnostic Trouble Code Index and follow the ACTION for each DTC given. Diagnostic Trouble Code Tests and Associated Procedures
- If a condition exists but no DTCs appear, GO to Symptom Chart Condition: The EATC System Is Inoperative, Intermittent or Incorrect Operation. Symptom Related Diagnostic Procedures
- To exit and retain all continuous DTCs, press any button except DEFROST. The EATC module will exit the retrieved continuous DTCs mode and retain all continuous DTCs.
- To exit and clear all continuous DTCs, press the DEFROST button. The EATC module 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 door actuators to automatically recalibrate.
- Continuous DTCs will be deleted after 80 ignition switch ON cycles after the intermittent fault occurs.