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 ON position, each module will begin 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 turned off.
Conditions for Running the DTC
The ABS conditions and the braking conditions are normal.
Conditions for Setting the DTC
DTC C1298 can be set any time the ignition is on, and the PCM does not receive any communications from the EBCM.
Action Taken When the DTC Sets
| • | A DTC C1298 is stored. |
| • | The TCS is disabled. |
| • | The TRAC OFF indicator is turned on. |
| • | The ABS remains functional. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and the scan tool clear DTC function is used. |
| • | 100 ignition cycles have passed with no DTCs detected. |
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. |
| • | An intermittent malfunction is most likely caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation. |
| • | Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems for intermittent problems. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the ABS Diagnostic System Check? | -- | ||
2 | Using the scan tool read the IPC (Instrument Panel Cluster) DTC(s). Is DTC U1040 set as a current IPC DTC? | -- | ||
3 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the repair? | -- | -- | |
4 |
Does the DTC reset? | -- | System OK |
