HVAC System Diagnostics (MTC)

Fault detection is through Diagnostic Trouble Codes (DTCs). DTCs are displayed by 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. DTCs pertaining to A/C compressor control circuits are stored in the PCM/ECM. For diagnostic tests for these DTCs, see SELF-DIAGNOSTICS - GRAND CHEROKEE article in ENGINE PERFORMANCE.