Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: Lack of communication may be due to 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.
- 3: This step tests for valid system power moding in all ignition switch positions.
- 5: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Data Link Connector (DLC) Schematics in Data Link Communications | |||
| 1 | Install a scan tool. Does the scan tool power up? | Go to Step 2 | Go to Scan Tool Does Not Power Up in Data Link Communications |
| 2 | Turn ON the ignition, with the engine OFF. Attempt to establish communication with the body control module. Does the scan tool communicate with the body control module? | Go to Step 3 | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications |
| 3 | IMPORTANT: Open the driver door and leave it open during this test. This will disable the RAP power mode and eliminate this power mode from the power mode parameter list. IMPORTANT: 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 parameter in the diagnostic circuit check menu on the scan tool. Rotate the ignition switch through all positions while observing the class 2 power mode parameter. Does the class 2 power mode parameter reading match the ignition switch position for all switch positions? | Go to Step 4 | Go to Power Mode Mismatch in Body Control System |
| 4 | Select the body control module display DTCs function on the scan tool. Does the scan tool display any DTCs? | Go to Step 5 | Go to Step 7 |
| 5 | Does the scan tool display any DTCs which begin with a "U"? | Go to Diagnostic Trouble Code (DTC) List in Data Link Communications | Go to Step 6 |
| 6 | Does the scan tool display DTC B1000 or B1440? | Go to Diagnostic Trouble Code (DTC) List in Body Control System | Go to Step 7 |
| 7 | Test the Courtesy Lamps for proper operation after closing and opening each door. Refer to Interior Lighting Systems Description and Operation in Lighting Systems. Do the Courtesy Lamps operate properly? | Go to Symptoms - Retained Accessory Power | Go to Symptoms - Lighting Systems in Lighting Systems |
| IMPORTANT |
|---|
| Open the driver door and leave it open during this test. This will disable the RAP power mode and eliminate this power mode from the power mode parameter list. |
| IMPORTANT |
|---|
| The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode. |
Diagnostic System Check - Retained Accessory Power
See also:
• Master Electrical Component List