Horns System 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.
- 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.
- Turn ignition switch to RUN position. Using scan tool, attempt to communicate with Body Control Module (BCM). 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.
- 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 horns system by symptom. See STEERING COLUMN SWITCHES - AZTEK article.
- 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.
- 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.
- If scan tool does not display DTC B1440, go to next step. If scan tool displays DTC B1440, go to DTC B1440 under DIAGNOSTIC TESTS.
- If scan tool displays DTC B1327 or B1328, repair engine electrical concern. See appropriate GENERATOR & REGULATOR article in STARTING & CHARGING SYSTEMS. If scan tool displays any other DTCs, perform appropriate test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .