Initial Inspection and Diagnostic Overview

Inspection and Verification

1. Verify the customer's original 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:
3. If the concern(s) remains after the inspection, perform the following EATC System Self Test:
- The EATC Self Test will detect concerns in the system control functions found during the Self Test and will display these error codes in addition to intermittent error codes for concerns that occur during system operation. The vehicle interior temperature should be between 60° F and 80° F when performing the Self Test. If the temperatures are not within the specified ranges, false in-car temperature sensor error codes will be displayed. Record all error codes displayed during the test.
- If any error codes appear during the Self Test, follow the diagnostics procedure given under "ACTION" for each error code given.
- If a condition exists but no error codes appear during the Self Test, refer to the Symptom Chart Condition: EATC System Inoperative, Intermittent or Improper Operation.
- The Self Test can be initiated at any time with any resulting error codes displayed. 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.
- To exit Self Test and retain error codes, push the blue (cooler) button. The control will exit Self Test, retain all error codes and then turn OFF (display blank).
- To exit Self Test and clear all error codes, press Defrost button. The VFD window will show 000 and all function symbols for one second. Then, the EATC Control Assembly will turn OFF (display blank) and all codes will be cleared.






The Self Test should be deactivated before powering the system down (system turned OFF). Intermittent error codes will be deleted after 80 ignition switch ON cycles after the intermittent condition occurs.