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DTC C0294, C120C, or C12F8

Diagnostic Instructions

    • 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.

DTC Descriptors

DTC C0294 00: Brake Switch and Brake Pedal Position Sensor Correlation Malfunction

DTC C120C 00: Brake Pedal Position Sensor 4 Plausibility

DTC C12F8 00: Brake Pedal Position Sensor 3 Plausibility

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

5 V Reference

C0110 00, C0880 00, C0880 02, C029C 5A, C120F 00, C12E0. 00, C12E5 00

C0110 00, C029C 03, C129A 00, C029 07, C029C 5A, C129E 00, C12E0 00

C0110 00, C0880 00, C029C 5A, C12E0 00, C12E5 00

C12B1 00, C12F8 00

Brake Control Brake Pedal Position Sensor Circuit 1 Terminal 4

C029C 03, C129A 00

C029C 03, C129A.00

C0110 00, C0880 00, C029C 5A, C12E0 00, C12E5 00

C12B1 00, C12F8 00

Brake Control Brake Pedal Position Sensor Circuit 2 Terminal 6

C029C 03, C129D 00

C0110 00, C029C 07, C129E 00, C12E0 00

C0110 00, C029C 07, C129E 00, C12E0 00

C12B1 00, C12F8 00

Low Reference

-

C0110 00, C0294 00, C029C 07, C029C 5A, C129E 00, C12E0 00, C12F8 00

-

C12B1 00, C12F8 00

Circuit/System Description

The electronic brake control module uses input from the brake control brake pedal position sensor and the brake pedal position sensor 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 control the amount of pressure applied to the wheels.

Conditions for Running the DTC

    • Ignition voltage is greater than 10 V.
    • Vehicle ON or Vehicle in Service Mode.

Conditions for Setting the DTC

    • The electronic brake control module detects an open in the low reference circuit.
    • The electronic brake control module detects that the two signal circuits do not match each other.

Action Taken When the DTC Sets

    • The ABS indicator turns ON.
    • The red brake indicator turns ON.
    • The traction control/stability control indicator turns ON.
    • The Service Brake Assist and Service StabiliTrak messages are displayed on the driver information centre.
    • The electronic brake control module disables the antilock brake system, the dynamic rear proportioning, the traction control system and the electronic stability control for the duration of the drive cycle.

Conditions for Clearing the DTC

    • The condition for setting the DTC is no longer present.
    • The history DTC will clear after 40 consecutive fault-free drive cycles have occurred.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Note: The 12 V battery must be able to maintain a charge during this brake sensor performance procedure. It is recommended that a charger/maintainer or equivalent be used to maintain proper battery voltage during this procedure.

  1. Vehicle in Service Mode with the transmission in PARK.
  2. Note: Do not depress the brake pedal during the Electronic Brake Control Module Learn.

  3. Perform the Electronic Brake Control Module Learn procedure with a scan tool.
  4. Note: To ensure the complete brake modulator and high pressure accumulator pressure relief procedure is allowed to occur; the brake controller must see 1 pedal apply with the propulsion system enabled, followed by a proper shutdown without applying the brake pedal.

  5. Vehicle ON, apply and release the brake pedal.
  6. Note: Vehicle OFF, without applying the brake pedal ensure the brake modulator and high pressure accumulator pressure relief occurs. This process will take approximately 1-3 minutes.

  7. Vehicle OFF, without applying the brake pedal,
  8. Remove the remote keyless entry transmitter and close all of the vehicle doors. Wait approximately 1-3 minutes until the brake modulator and the high pressure accumulator pressure relief is complete and the vehicle powers down.
  9. Vehicle ON, brakes not applied.
  10. Verify the scan tool parameters listed below are within the specified range:
  11. • Brake Controls Brake Pedal Position Sensor 5 V Supply Voltage - Between 4.75-5.25 V.
    • Brake Controls Brake Pedal Position Sensor Circuit 1 - Between 1.4-1.7 V
    • Brake Controls Brake Pedal Position Sensor Circuit 2 - Between 58 78%
    If any parameter is not within the specified range
        Refer to Circuit/System Testing.
    ⇓   If all parameters are within the specified range
  12. Vehicle ON, brakes not applied.
  13. Verify the scan tool parameters listed below are less the specified range:
  14. • Brake Master Cylinder Pressure Sensor - Less than 100 kPa (15 psi)
    • Brake Pressure Sensor - Less than 100 kPa (15 psi)
    • High Pressure Accumulator Sensor - Less than 800 kPa (116 psi)
    If any parameter is greater than the specified range
        Replace the Q5 brake pressure modulator.
    ⇓   If all parameters are less than the specified range
  15. Perform a brake hydraulic system test, refer to Brake Hydraulic and Assist System Diagnosis .
  16. If the brake hydraulic system test does not pass
        Repair as necessary.
    ⇓   If the brake hydraulic system tests normal
  17. Replace the Q5 brake pressure modulator.
  18. Verify the DTC does not set while operating the vehicle under the Conditions for Running the DTC.
  19. If the DTC sets
        K17 electronic brake control module.
    ⇓   If the DTC does not set
  20. All OK.

Circuit/System Testing

  1. Perform the brake hydraulic check, refer to Brake Hydraulic and Assist System Diagnosis .
  2. Vehicle OFF, disconnect the harness connector at the B201 brake control brake pedal position sensor.
  3. Test for less than 5 Ω between the low reference circuit terminal 1 and ground.
  4. If 5 Ω or greater
    3.1. Vehicle OFF, disconnect the harness connector at the K17 electronic brake control module.
    3.2. Test for less than 2 Ω in the low reference circuit end to end.
    ⇒     If 2 Ω or greater, repair the open/high resistance in the circuit.
    ⇒     If less than 2 Ω, replace the K17 electronic brake control module.
    ⇓   If less than 5 Ω
  5. Vehicle in Service Mode.
  6. Test for 4.8-5.2 V between the 5 V reference circuit terminal 5 and ground.
  7. If less than 4.8 V
    5.1. Ignition OFF, disconnect the harness connector at the K17 electronic brake control module.
    5.2. Test for infinite resistance between the 5 V reference circuit and ground.
    ⇒     If less than infinite resistance, repair the short to ground on the circuit.
    ⇓     If infinite resistance
    5.3. Test for less than 2 Ω in the 5 V reference circuit end to end.
    ⇒     If 2 Ω or greater, repair the open/high resistance in the circuit.
    ⇒     If less than 2 Ω, replace the K17 electronic brake control module.
    If greater than 5.2 V
    5.1. Vehicle OFF, disconnect the harness connector at the K17 electronic brake control module, vehicle in service mode.
    5.2. Test for less than 1 V between the 5 V reference circuit and ground.
    ⇒     If 1 V or greater, repair the short to voltage on the circuit.
    ⇒     If less than 1 V, replace the K17 electronic brake control module.
    ⇓   If between 4.8-5.2 V
  8. Verify the scan tool Brake Controls Brake Pedal Position Sensor Circuit 1 parameter is less than 1 V.
  9. If 1 V or greater
    6.1. Vehicle OFF, disconnect the harness connector at the K17 electronic brake control module, vehicle in service mode.
    6.2. Test for less than 1 V between the signal circuit terminal 4 and ground.
    ⇒     If 1 V or greater, repair the short to voltage on the circuit.
    ⇒     If less than 1 V, replace the K17 electronic brake control module.
    ⇓   If less than 1 V
  10. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the 5 V reference circuit terminal 5.
  11. Verify the scan tool Brake Controls Brake Pedal Position Sensor Circuit 1 parameter is greater than 4.5 V.
  12. If 4.5 V or less
    8.1. Vehicle OFF, disconnect the harness connector at the K17 electronic brake control module.
    8.2. Test for infinite resistance between the signal circuit terminal 4 and ground.
    ⇒     If less than infinite resistance, repair the short to ground on the circuit.
    ⇓     If infinite resistance
    8.3. Test for less than 2 Ω in the signal circuit end to end.
    ⇒     If 2 Ω or greater, repair the open/high resistance in the circuit.
    ⇒     If less than 2 Ω, replace the K17 electronic brake control module.
    ⇓   If greater than 4.5 V
  13. Verify the scan tool Brake Controls Brake Pedal Position Sensor Circuit 2 parameter is greater than 80%.
  14. If 80% or less
    9.1. Vehicle OFF, disconnect the harness connector at the K17 electronic brake control module.
    9.2. Test for infinite resistance between the signal circuit terminal 6 and ground.
    ⇒     If less than infinite resistance, repair the short to ground on the circuit.
    ⇒     If infinite resistance, replace the K17 electronic brake control module.
    ⇓   If greater than 80%
  15. Install a 3 A fused jumper wire between the signal circuit terminal 6 and the low reference circuit terminal 1.
  16. Verify the scan tool Brake Controls Brake Pedal Position Sensor Circuit 2 is less than 10%.
  17. If 10% or greater
    11.1. Vehicle OFF, disconnect the harness connector at the K17 electronic brake control module, vehicle in service mode.
    11.2. Test for less than 1 V between the signal circuit terminal 6 and ground.
    ⇒     If 1 V or greater, repair the short to voltage on the circuit.
    ⇓     If less than 1 V
    11.3. Vehicle OFF.
    11.4. Test for less than 2 Ω in the signal circuit end to end.
    ⇒     If 2 Ω or greater, repair the open/high resistance in the circuit.
    ⇒     If less than 2 Ω, replace the K17 electronic brake control module.
    ⇓   If less than 10%
  18. Replace the B201 brake control brake pedal position sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

    •  Electronic Brake Control Position Sensor Replacement
    • Control Module References for electronic brake control module replacement, programming and setup
   


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