Circuit Description
The serial data line allows all the modules on the line to transmit information to each other as needed. Each module on the serial data line knows what information it needs to send out and what information it should be receiving.
Conditions for Running the DTC
DTC 72 can be set anytime the ignition switch is in the ON position.
Conditions for Setting the DTC
The electronic brake control module (EBCM) cannot communicate with the body control module (BCM).
Action Taken When the DTC Sets
| • | The EBCM disables the traction control system for the duration of the ignition cycle. |
| • | The TRAC OFF warning indicator turns ON. |
Conditions for Clearing the DTC
The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTCs function is used.
Diagnostic Aids
Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.
The following are possible causes of the malfunction:
| • | An open, high resistance, short to ground or short to voltage in the EBCM UART SEC circuit |
| • | An internal BCM malfunction |
| • | An internal EBCM malfunction |
If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to step numbers on the diagnostic table.
-
This step tests the UART SEC circuit of the EBCM for an open, high resistance, short to ground or short to voltage.
-
This step tests the UART SEC circuit of the EBCM for an open or high resistance.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views | ||||
1 | Did you perform A Diagnostic System Check - ABS? | -- | Go to Step 2 | |
2 |
Does the DTC reset? | -- | Go to Step 3 | Go to Diagnostic Aids |
3 | Use the scan tool in order to communicate with the body control module (BCM). Does the scan tool communicate with the BCM? | -- | Go to Step 4 | Go to Diagnostic Starting Point - Body Control System in Body Control System |
4 | Use the scan tool in order to read the DTCs for the IPC module and Radio. Are any serial data DTCs set? | -- | Go to Step 5 | Go to Step 6 |
Test the electronic brake control module (EBCM) UART circuit for an open, high resistance, short to ground or short to voltage. Refer to Circuit Testing in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7 | |
Test the EBCM UART circuit for an open or high resistance. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8 | |
7 | Replace the BCM. Refer to Body Control Module Replacement in Body Control Systems. Did you complete the replacement? | -- | Go to Step 9 | -- |
8 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
