Air Conditioning System Diagnostic System Check

Connect scan tool to Data Link Connector (DLC). DLC is located on left side of instrument panel, near steering column. If scan tool powers up, go to next step. If scan tool does not power up, go to TEST A: SCAN TOOL DOES NOT POWER UP under SYSTEM TESTS.
Turn ignition switch to RUN position. Attempt to establish communication with Powertrain Control Module (PCM). If scan tool communicates with PCM, go to next step. If scan tool does not communicate with PCM, go to TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS.
Select DISPLAY DTCs function on scan tool for PCM. If scan tool displays any DTCs, go to next step. If scan tool does not display any DTCs, diagnose and repair A/C system by symptom:
- On 2001 models, see MANUAL A/C-HEATER SYSTEMS - CAVALIER & SUNFIRE article in HVAC.
- On 2002 models, see MANUAL A/C-HEATER SYSTEMS - CAVALIER & SUNFIRE article in HVAC.
If communication DTCs (DTCs beginning with a "U") are not retrieved, go to next step. If any DTCs beginning with "U" are retrieved, go to TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS.
If any powertrain DTCs (DTCs beginning with "P") related to A/C system are retrieved, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs beginning with "P" related to A/C system are retrieved, diagnose and repair powertrain concern. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.