Circuit Description
The Class 2 serial data line allows all the modules on the line to transmit information to each other as needed. Each module is assigned an ID and all the information sent out on the line is assigned a priority by which it is received. When the ignition switch is turned to the run position each module begins to send and receive information. Each module on the Class 2 serial data line knows what information it needs to send out and what information it should be receiving. What the modules do not know is which module is supposed to send them the information. This information is only learned after the module has received the information it needs along with the ID of the module that sent the information. This information is then remembered until the ignition switch is truned off.
Diagnostic Aids
| • | 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 system. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
DEFINITION: Scan tool can not communicate with the EBCM/EBTCM. | ||||
1 | Was the Diagnostic System Check performed? | -- | ||
2 | Turn the Ignition switch to the RUN position with the engine off. Can the scan tool communicate with other modules on the Class 2 serial data line, such as the PCM? | -- | Go to Data Link Connector System Check in Wiring Systems | |
3 | Inspect the 10A ABS IGN fuse in the Underhood Electrical Center 2. Is the fuse OK? | -- | ||
4 |
Is the voltage within the range specified within the value(s) column? | Battery Volts | Go to Power Distribution in Wiring Systems | |
5 |
Is the resistance within the range specified in the value(s) column? | 0-5 ohms | ||
6 |
Is the fuse OK? | -- | ||
7 |
Is the resistance within the range specified in the value(s) column? | OL (infinite) | ||
8 | Repair CKT 739 for a short to ground. Refer to Wiring Repairs . Is the repair complete? | -- | -- | |
9 | Repair CKT 651 or G101 for an open or high resistance. Refer to Wiring Repairs . Is the repair complete? | -- | -- | |
10 |
Is the voltage within the range specified in the value(s) column? | Battery Volts | ||
11 | Repair CKT 739 for an open. Refer to Wiring Repairs . Is the repair complete? | -- | -- | |
12 | Replace the EBCM/EBTCM. Refer to Electronic Brake Control Module Replacement . Is the replacement complete? | -- | -- | |
