Diagnostic System Check - HVAC System - Manual

DIAGNOSTIC SYSTEM CHECK - HVAC SYSTEMS - MANUAL

TEST DESCRIPTION

Steps 1-6:

Steps 7-8:

The numbers below refer to the step numbers on the diagnostic table.
3. Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit.
The specified procedure will determine the particular condition.
4. This step determines if the powertrain control module (PCM) has set DTCs which may affect HVAC operation are present.
5. The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
8. If there are HVAC control module DTCs present, then the LEDs for the A/C request switch, recirculation switch or the rear defrost switch will flash indicating a current DTC.