HVAC System Diagnostics (AZC)

Fault detection is through active and stored Diagnostic Trouble Codes (DTCs). DTCs are displayed by the DRBIII(R). AZC Module DTCs are active or stored.

Active DTCs are those which currently exist in the system. The condition causing the fault must be repaired in order to clear this type of DTC. Active DTCs become stored DTCs when the condition that caused the active DTC no longer exists.

Stored DTCs will be erased after 72 key cycles or by clearing them with the DRBIII(R).

DTCs pertaining to the Evaporator Temperature Sensor are stored in the BCM. Diagnostics for these DTCs can be found in HVAC  under DIAGNOSTIC TESTS. Diagnostics for symptoms pertaining to A/C compressor operation can be found in HVAC  under SYMPTOM TESTS and in SELF-DIAGNOSTICS - GRAND CHEROKEE article in ENGINE PERFORMANCE. See appropriate AUTOMATIC A/C-HEATER SYSTEMS article in HVAC for additional AZC system diagnosis and testing information.