Circuit Description
The electronic brake control module (EBCM) monitors the voltage level available for system operation. A low voltage condition prevents the system from operating properly.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC C0899 Device Voltage Low
Conditions for Running the DTC
The system relay is commanded ON.
Conditions for Setting the DTC
One of the following conditions exists for 0.72 second:
| • | During initialization or when the system is inactive, the system voltage is less than 10.5 volts. |
| • | During the system operation, the system voltage is less than 9 volts. |
Action Taken When the DTC Sets
| • | The EBCM disables the ABS and dynamic rear proportion (DRP) is degraded when the code is current. |
| • | The ABS indicator turns ON. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and the DTC is cleared with a scan tool. |
| • | The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
Diagnostic Aids
| • | Test the charging system. Refer to Diagnostic System Check - Vehicle in Vehicle DTC Information. |
| • | Possible causes of this DTC are the following conditions: |
| - | A charging system malfunction |
| - | An excessive battery draw |
| - | A weak battery |
| - | A faulty system ground |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Use the scan tool in order to inspect the voltage to the EBCM.
-
This step verifies that the condition is still present.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
Does the scan tool indicate the voltage is greater than the specified value? | 10.5 V | Go to Diagnostic Aids | Go to Step 3 | |
3 | With a scan tool, observe the Ignition Voltage Signal parameter in the ABS data list. Does the scan tool indicate the voltage is greater than the specified value? | 10.5 V | Go to Step 4 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
4 | Test the ground circuits of the electronic brake control module (EBCM) including the EBCM ground for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 7 | Go to Step 5 |
Does the DTC reset? | -- | Go to Step 6 | Go to Diagnostic Aids | |
6 | Replace the EBCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the repair? | -- | Go to Step 7 | -- |
7 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
