Door Systems Diagnostic System Check
NOTE:
The presence of DTCs which begin with "U" indicate some other module on class 2 serial data line is not communicating.
NOTE:
Lack or loss of communication may be due to partial malfunction of class 2 serial data circuit, or total malfunction of class 2 serial data circuit.
- Connect scan tool to Data Link Connector (DLC). DLC is located under left side of instrument panel. 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 in BODY CONTROL MODULES - AZTEK article.
- Turn ignition switch to RUN position. Attempt to establish communication with Body Control Module (BCM) on class 2 serial data circuit. If scan tool communicates with BCM, go to next step. If scan tool does not communicate with BCM, go to TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in BODY CONTROL MODULES - AZTEK article.
- Using scan tool, access class 2 power mode from diagnostic circuit check function. Rotate ignition switch through all positions while observing ignition switch power mode parameter on scan tool. If ignition switch parameter reading matches ignition switch position for all switch positions, go to next step. If ignition switch parameter reading does not match ignition switch position for all switch positions, go to TEST C: POWER MODE MISMATCH under SYSTEM TESTS in BODY CONTROL MODULES - AZTEK article.
- Using scan tool, select DISPLAY DTCS function. Retrieve and record any BCM DTCs and their status. If scan tool displays any DTCs, go to next step. If scan tool does not display any DTCs, repair power windows by symptom. See SYMPTOM INDEX table under SYSTEM TESTS.
- If scan tool does not display any DTCs which begin with a "U", go to next step. If scan tool displays any DTCs which begin with a "U", go to TEST B: SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in BODY CONTROL MODULES - AZTEK article.
- If scan tool does not display DTC B1000, go to next step. If scan tool displays DTC B1000, go to DTC B1000: BODY CONTROL MODULE MALFUNCTION under DIAGNOSTIC TESTS in BODY CONTROL MODULES - AZTEK article.
- If scan tool does not display DTC B1477 or B1478, go to next step. If scan tool displays DTC B1477 or B1478, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS under SELF-DIAGNOSTICS in BODY CONTROL MODULES - AZTEK article.
- If scan tool does not display any DTCs beginning with a "P", go to next step. If scan tool displays any DTCs beginning with a "P", see appropriate SELF DIAGNOSTICS article in ENGINE PERFORMANCE.
- If scan tool displays DTCs B1349, B3069, B3270, or B3272, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS under SELF-DIAGNOSTIC SYSTEM in POWER DOOR LOCKS - AZTEK article. If scan tool does not display any DTCs, repair power windows by symptom. See SYMPTOM INDEX table under SYSTEM TESTS.
NOTE:
Engine may start during following step. Turn off engine as soon as you have observed crank power mode.