- Perform the Battery Inspection/Test. See BATTERY TESTING & INSPECTION in GENERATORS & REGULATOR
. Does the battery pass the test? If so, go to next step.
- Install a scan tool. Turn ON the ignition, with the engine OFF. Does the scan tool power up? If so, go to next step. If not, go to SCAN TOOL DOES NOT POWER UP in BODY CONTROL MODULES
.
NOTE:
The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.
- Access the CLASS 2 POWER MODE in the DIAGNOSTIC CIRCUIT CHECK on the scan tool. Rotate the ignition switch through OFF, RUN, and CRANK positions while observing the ignition switch power mode parameter. Does the ignition switch parameter reading match the ignition switch positions for OFF, RUN and CRANK positions? If so, go to next step. If not, go to POWER MODE MISMATCH in BODY CONTROL MODULES
.
- Turn ON the ignition, with the engine OFF. Attempt to communicate with each of the following modules on the class 2 serial data circuit:
- Body Control Module (BCM)
- Driver Information Center (DIC)
- Powertrain Control Module (PCM)
- Instrument Panel Cluster (IPC)
Does the scan tool communicate with all modules on the class 2 serial data circuit? If so, go to next step. If not, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in BODY CONTROL MODULES
.
NOTE:
Lack of communication may be because of a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
- Select the DISPLAY DTCS function for each module. (If using a Tech 2, use the CLASS 2 DTC CHECK feature in order to determine which modules have DTCs set.) Record all of the displayed DTCs the DTC status and the module which set the DTC. Does the scan tool display any DTCs? If so, go to next step. If not, go to SYMPTOMS - ENGINE ELECTRICAL .
NOTE:
The symptom list in Symptoms will determine the correct diagnostic procedure to use.
- Does the scan tool display any DTC beginning with "U"? If so, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in BODY CONTROL MODULES
. If not, go to next step.
NOTE:
The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will collect all the available information before you perform tests.
- Does the scan tool display any DTC beginning with "B"? If so, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in BODY CONTROL MODULES
. If not, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS .