Test AF: Malfunction Indicator Lamp Always On: Testing
- If engine controls diagnostic system check has been performed, go to next step. If engine controls diagnostic system check has not been performed, see ENGINE CONTROLS DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in BODY CONTROL MODULES - AZTEK article.
- Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). DLC is located under left side of instrument panel. Turn ignition switch to RUN position. Using scan tool, retrieve any DTCs. If no DTC's are set, go to next step. If any DTC's are set, perform appropriate test. See DIAGNOSTIC SYSTEMS CHECK INDEX table under SELF-DIAGNOSTIC SYSTEM.
- Turn ignition switch to OFF position. Observe MIL on instrument panel cluster. If MIL is not illuminated, go to next step. If MIL is illuminated, go to step 6.
- Using scan tool, command MIL on and off several times while monitoring instrument panel. If MIL does not turn on and off as commanded, go to next step. If MIL turns on and off as commanded, go to MALFUNCTION INDICATOR LIGHT OPERATION .
- Check for short to ground in MIL control circuit, Brown/White wire between Powertrain Control Module (PCM) harness connector C2 terminal No. 5 and Instrument Panel Cluster (IPC) harness connector terminal A2. See Figure and Figure . If problem exists, repair as necessary and go to step 7.
- Check for short to voltage in MIL control circuit, Brown/White wire between Powertrain Control Module (PCM) harness connector C2 terminal No. 5 and Instrument Panel Cluster (IPC) harness connector terminal A2. If problem exists, repair as necessary and go to step 7.
- Using scan tool, command MIL on and off several times while monitoring instrument panel. If MIL turns on and off as commanded, perform engine controls diagnostic system check, see ENGINE CONTROLS DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in BODY CONTROL MODULES - AZTEK article. If MIL does not turn on and off as commanded, go to go to step 2.