Diagnostic Procedure
- Perform battery test and inspection. See BATTERY TESTING & INSPECTION under ON-VEHICLE TESTING. If battery passed test, go to next step. If battery did not pass test, replace battery.
- Connect scan tool to Data Link Connector (DLC). DLC is located below left side of instrument panel. Turn ignition switch to RUN position. If scan tool powers up, go to next step. If scan tool does not power up, perform appropriate test in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
- Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool. Rotate the ignition switch through all positions while observing the Class 2 Power Mode parameter. The ignition switch parameter reading should match the ignition switch position for all switch positions. If reading is as specified, go to next step. If reading is not as specified, see appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
- Turn ignition switch to RUN position. Using scan tool, attempt to communicate with Body Control Module (BCM), Driver's Information Center (DIC), Instrument Panel Cluster (IPC) and Powertrain Control Module (PCM). If scan tool communicates with BCM, DIC, IPC and PCM, go to next step. If scan tool does not communicate with BCM, DIC, IPC and PCM, perform appropriate test in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
- Using scan tool, select DISPLAY DTC's function for each module. Record all DTC's displayed, DTC status and specific module which set DTC. If scan tool displays any DTC's, go to next step. If scan tool does not display DTC's, repair starting system by symptom. See SYMPTOM INDEX table under SYSTEM TESTS.
- If scan tool displays DTC's which begin with "U", perform appropriate test in accordance with DTC retrieved. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If scan tool does not display DTC's which begin with "U", go to next step.
- If scan tool displays DTC's which begin with "B", perform appropriate test in accordance with DTC retrieved. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If scan tool does not display DTC's which begin with "B", perform appropriate test in accordance with DTC retrieved. See DIAGNOSTIC TROUBLE CODE DEFINITIONS .
NOTE:
The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.