Circuit Description
The serial data UART allows information to be exchanged from module to module as needed. This is done by the PCM. The PCM requests and sends all of the information that is transmitted via serial data UART. When the scan tool is connected to the serial data UART, the scan tool takes over for the PCM and sends and requests the needed information.
Diagnostic Aids
| • | It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. |
| • | An intermittent malfunction can be caused by poor connections, broken insulation, or a wire that is broken inside the insulation. |
| • | If an intermittent malfunction exists, refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
DEFINITION: The scan tool will not communicate with the EBCM/EBTCM. | ||||
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | |
2 | Turn the ignition switch to the RUN position with the engine off. May the scan tool communicate with other modules on the UART serial data line, such as the PCM? | -- | Go to Step 3 | Go to Data Link Communications System Check in Data Link Communications |
3 | Inspect the ABS/CCR Fuse in the IP fuse block. Is the fuse OK? | -- | Go to Step 4 | Go to Step 8 |
4 | Inspect the ABS SOL Fuse in the LH underhood fuse block. Is the fuse OK? | -- | Go to Step 10 | Go to Step 5 |
5 |
Is the resistance within the specified range? | OL (infinite) | Go to Step 6 | Go to Step 7 |
6 | Replace the EBCM/EBTCM. Refer to Electronic Brake Control Module Replacement . Did you complete the repair? | -- | -- | |
7 | Repair a short to ground CKT 342 (RED). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
8 |
Is the resistance within the specified range? | OL (infinite) | Go to Step 6 | Go to Step 9 |
9 | Repair a short to ground CKT 641 (BRN). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
10 |
Is the voltage within the specified range? | Battery Voltage | Go to Step 11 | Go to Wiring Repairs in Wiring Systems |
11 | Use the J 39200 DMM in order measure the voltage at the ABS SOL Fuse by probing between the fuse test terminals and a good ground. Is the voltage within the specified range? | Battery Voltage | Go to Step 12 | Go to Wiring Repairs in Wiring Systems |
12 |
Is the resistance less than the specified value? | 2 ohms | Go to Step 14 | Go to Step 13 |
13 | Repair an open or high resistance in CKT 1050 (BLK) or G106. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
14 |
Is the voltage within the specified range? | Battery Voltage | Go to Step 16 | Go to Step 15 |
15 | Repair an open in CKT 641 (BRN). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
16 | Use the J 39200 DMM in order to measure the voltage between the J 39700 terminal D and terminal B. Is the voltage within the specified range? | Battery Voltage | Go to Step 6 | Go to Step 17 |
17 | Repair an open in CKT 342 (RED). Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
