DTC C1298 PCM Class 2 Serial Data Link Malfunction w/NW9
Circuit Description
The class 2 serial data line allows all of the modules on the line to transmit information to each other as needed. Each module is assigned an ID. All of the information sent out on the line is assigned a priority by which it is received. When the ignition is turned ON, each module begins to send and receive information. Each module on the class 2 serial data line knows what information the module needs to send out and what information the module should be receiving. What the modules do not know is which module is supposed to send the information. This information is only learned after the module has received the information needed 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
The PCM does not receive any messages from the EBCM for 7 seconds.
Action Taken When the DTC Sets
| • | The EBCM disables the TCS for the duration of the ignition cycle. |
| • | The TRAC OFF indicator turns ON. |
| • | The ABS remains functional. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and the DTC is cleared with a scan tool. |
| • | The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
Diagnostic Aids
Possible causes of this DTC are the following conditions:
| • | The EBCM has a class 2 serial data transmit fault. |
| • | The PCM has a class 2 serial data receiver fault. |
| • | The class 2 serial data line has an extremely high amount of traffic. |
| • | Loose or corroded EBCM ground or PCM ground. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | |||||||||
Does the scan tool display DTC U1040? | -- | Go to Scan Tool Does Not Communicate with Class 2 Device in Data Link Communications | Go to Step 3 | |||||||||
3 | Inspect the EBCM ground and PCM ground, making sure each ground is clean and torqued to the proper specification. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 4 | ||||||||
4 |
Did the scan tool display the correct ignition switch positions? | -- | Go to Step 5 | Go to Diagnostic System Check - Body Control System in Body Control System | ||||||||
5 | Suspect the PCM. Refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 3.8L. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 6 | ||||||||
6 |
Does the DTC reset? | -- | Go to Step 7 | Go to Diagnostic Aids | ||||||||
7 |
Important: Perform the setup procedure for the EBCM. An unprogrammed EBCM will
result in the following conditions:
Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | -- | Go to Step 8 | -- | ||||||||
8 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
