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 turned off. If the EBTCM looses communication with the Continuously Variable Road Sensing Suspension Module (CVRSS) then DTC U1056 will be set by the EBTCM.
Conditions for Setting the DTC
The DTC can be set any time the ignition is in the RUN position, and the CVRSS module does not communicate with the EBTCM for 7 seconds.
Action Taken When the DTC Sets
| • | A malfunction DTC is stored. |
| • | The ABS remains functional. |
| • | The ABS indicator remains OFF. |
Conditions for Clearing the DTC
| • | The condition for DTC is no longer present and you used scan tool Clear DTCs function. |
| • | The condition for DTC is no longer present and you used the On-Board Clear DTCs function. |
| • | The EBTCM does not detect the DTC in 50 drive cycles. |
Diagnostic Aids
| • | Perform a thorough inspection of the wiring and the connectors. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. |
| • | An intermittent malfunction may 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 . |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check |
2 | Using a scan tool read the PCM DTCs. Is DTC P1611 also set as a current PCM DTC? | -- | Go to Road Sensing Suspension Diagnostic System Check in Road Sensing Suspension-RSS | Go to Step 3 |
3 | Is DTC U1056 set as a current ABS/TCS/ICCS DTC? | -- | Go to Step 4 | Go to Diagnostic System Check |
4 | Replace the EBTCM. Refer to Electronic Brake Control Module Replacement . Is the replacement complete? | -- | Go to Diagnostic System Check | -- |
