• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
5-Volt Reference | C0277 5A, C12B1, C12F8, C120C, C0161 04, C127D, C0880 00, C12E5, C0880 02, C120F | C0277 03, C129A, C129D, C0277 5A, C12B1, C12F8, C120C, C0161 04, C127D | C0277 5A, C12B1, C12F8, C120C, C0161 04, C127D, C0880 00, C12E5, | C0277 5A, C12B1, C12F8, C120C |
Brake Master Cylinder Piston Position Sensor Signal Terminal 35 | C0277 03, C129A, C129D | C0277 03, C129A, C129D, C0277 5A, C12B1, C12F8, C120C, C0161 04, C127D | C0277 5A, C12B1, C12F8, C120C, C0161 04, C127D, C0880 00, C12E5 | C0277 5A, C12B1, C12F8, C120C |
Brake Master Cylinder Piston Position Sensor Signal Terminal 9 | C0277 03, C129A, C129D | C0277 03, C129A, C129D, C0277 5A, C12B1, C12F8, C120C, C0161 04, C127D | C0277 5A, C12B1, C12F8, C120C, C0161 04, C127D, C0880 00, C12E5 | C0277 5A, C12B1, C12F8, C120C |
Low Reference | C0294 00, C120C, C12F8, C0161 04, C127D, C0880 00, C12E5, C0455 39 | -- | -- | C0277 5A, C12B1, C12F8, C120C |
The electronic brake control module (EBCM) uses input from the brake master cylinder piston position sensor and the brake switch to determine when the brake pedal is being applied and with how much force. These inputs are used to determine the driver's braking intent which is used to the control amount of pressure applied to the wheels.
• | Ignition ON. |
• | Ignition voltage is greater than 10 volts. |
• | The EBCM detects an open in the low reference circuit. |
• | The EBCM detects that the two signal circuits do not match each other. |
• | The EBCM disables the antilock brake system (ABS), traction control and the vehicle stability enhancement system (VSES) for the duration of the ignition cycle. |
• | A DIC message and/or a warning indicator may be displayed. |
• | The condition for the DTC is no longer present. |
• | The EBCM clears the history DTC when a current DTC is not detected in 40 consecutive drive cycles. |
Antilock Brake System Schematics
Control Module References for scan tool information
Ignition ON, use a scan tool to observe the EBCM BMC Primary Piston Position Sensor A and B parameter while applying and releasing the brake pedal. The voltage should change between 0 and 5 volts.
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. |
⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. |
⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. |
⇒ | If greater than the specified range, test the signal circuit terminal 1 for a short to voltage. |
⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. |
⇒ | If greater than the specified range, test the signal circuit terminal 3 for a short to voltage. |
⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for EBCM replacement, setup, and programming |