Electronic Climate Control

1. Verify the customer's concern by operating the electronic automatic temperature control to duplicate the condition.
2. Inspect to determine if one of the following mechanical or electrical concerns apply:

VISUAL INSPECTION

Mechanical
- Vacuum hose damaged.
- A/C system damaged.
- Damaged drive belt.

Electrical
- Open fuse(s).
- circuitry misrouted/damaged.
- connectors damaged/disconnected.

3. If inspection reveals an obvious concern that is readily serviced, correct the concern before continuing with Inspection and Verification.
4. If a concern remains after the inspection, use the Rotunda New Generation STAR (NGS) Tester 418-F048(007-00500) or equivalent connected to the Data Link Connector (DLC) and select the vehicle to be tested from the NGS menu. If the vehicle selection cannot be entered:
- check that the program card is properly installed.
- check the connections to the vehicle.
- check the ignition switch position. If the NGS still does not allow the vehicle selection to be entered.
5. Perform the DATA LINK DIAGNOSTIC TEST using the NGS. If the NGS responds with:
a. CKT914 and CKT915 = ALL MODULE NO RESP/NOT EQUIP.
b. If the EATC module is not listed for a communication concern, execute self-test diagnostics for the EATC module.
c. If the Powertrain Control Module (PCM) is not listed for a communication concern, turn the EATC module OFF and execute self-test diagnostics for the PCM.
6. If the EATC or PCM DTCs retrieved are related to the concern, go to the EATC Module Diagnostic Trouble Code Index or the PCM Diagnostic Trouble Code Index to continue diagnostics. With Electronic Climate Control
7. If no DTCs related to the concern are retrieved, go to the Symptom Chart to continue diagnostics. Electronic Climate Control
8. If the electronic automatic temperature control module cannot be accessed by the NGS Tester, go to Pinpoint Test E. E: No Communication With EATC Module
- The EATC module self-test will not detect concerns associated with data link messages like engine coolant temperature or vehicle speed signals. An NGS tester must be used to retrieve these concerns.
- The EATC module self-test will detect concerns in the system control functions and will display hard DTCs and intermittent DTCs for concerns occurring during system operation. The vehicle interior temperature should be between 4°C (40°F) and 32°C (90°F) when performing the self-test. If the temperatures are not within the specified ranges, false in-car temperature sensor DTCs will be displayed.
- The self-test can be initiated at any time. Normal operation of the system stops when the self-test is activated.
- To enter the self-test, press the OFF and FLOOR buttons simultaneously and then press the AUTOMATIC button within two seconds. The display will show a pulse tracer going around the center of the display window. The test may run as long as 30 seconds. Record all DTCs displayed.
- If any DTCs appear during the self-test, follow the diagnostics procedure given under ACTION for each DTC given.
- If a condition exists but no DTCs appear during the self-test, refer to the Symptom Chart Condition: EATC System Inoperative, Intermittent or Improper Operation. Electronic Climate Control
- To exit selftest and retain all intermittent DTCs, push the blue (cooler)' button. The control will exit self-test, retain all intermittent DTCs and then turn OFF (display blank).
- To exit self-test and clear all DTCs, press Defrost button. The vacuum fluorescent display window will show 888 and all function symbols for one second. Then, the EATC Control will turn OFF (display blank) and all DTCs will be cleared.

Always exit the self-test before powering the system down (system turned OFF). Intermittent DTCs will be deleted after 80 ignition switch ON cycles (after the intermittent condition occurs).