The UART serial data link allows information to be exchanged from module to module as needed. This is done by the PCM, the PCM requests and sends all the information that is transmitted on the UART line. When a scan tool is connected to the UART line it takes over for the PCM and sends and requests the needed information.
• | Thoroughly inspect the wiring and the connectors. Failure to carefully and fully inspect the wiring and the connectors can result in misdiagnosis. Misdiagnosis may cause replacement of parts without repairing the malfunction. |
• | If an intermittent malfunction exists, refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. |
Step | Action | Value(s) | Yes | No |
---|---|---|---|---|
DEFINITION: Scan tool can not communicate with the EBCM/EBTCM. | ||||
1 | Was the Diagnostic System Check performed? | -- | Go to Diagnostic System Check | |
2 | Turn the ignition switch to the RUN position with the engine off. Can the scan tool communicate with other modules on the UART serial data line, such as the PCM? | -- | Go to Data Link Communications System Check | |
3 | Inspect the 10A ABS/CCR fuse in the IP fuse block. Is the fuse OK? | -- | ||
4 | Inspect the 40A ABS SOL fuse in the LH underhood fuse block. Is the fuse OK? | -- | ||
5 |
Is the fuse OK? | -- | Go to Diagnostic System Check | |
6 |
Is the resistance equal to the specified value? | OL (infinite) | ||
7 | Replace the EBCM/EBTCM. Refer to Electronic Brake Control Module Replacement . Is the replacement complete? | -- | Go to Diagnostic System Check | -- |
8 | Repair CKT 342 for a short to ground. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
9 |
Is the fuse OK? | -- | Go to Diagnostic System Check | |
10 |
Is the resistance equal to the specified value? | OL (infinite) | ||
11 | Repair CKT 641 for a short to ground. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
12 |
Is the voltage within the specified range? | Battery Voltage | Go Wiring Repairs in Wiring Systems | |
13 | Using the J 39200 DMM, measure the voltage at the 40A ABS SOL fuse by probing between the fuse test terminals and a good ground. Is the voltage within the specified range? | Battery Voltage | Go Wiring Repairs in Wiring Systems | |
14 |
Is the resistance less than the specified value? | 2 ohms | ||
15 | Repair CKT 1050 or G106 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
16 |
Is the voltage within the specified range? | Battery Voltage | ||
17 | Repair CKT 641 for an open. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |
18 | Using the J 39200 DMM, measure the voltage between J 39700 terminals D and B. Is the voltage within the specified range? | Battery Voltage | ||
19 | Repair CKT 342 for an open. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | -- |