C0299
DTC C0299 or C12FF
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC C0299 00
- Brake Booster Performance Malfunction
DTC C12FF 00
- Electronic Brake Control Module Non-Volatile RAM Malfunction
DTC C0299 31
- Brake Booster Performance Internal Checksum Error
Circuit/System Description
The electronic brake control module uses inputs from the brake master cylinder piston position sensor and the brake pedal position sensor to determine when the brake pedal is being applied and with how much force. These inputs determine the driver's braking intent which is used to control the amount of pressure applied to the wheels.
Conditions for Running the DTC
* Vehicle ON or Vehicle in Service Mode.
* The ignition voltage is greater than 10 V.
Conditions for Setting the DTC
* The brake pedal is sensed as applied for 6 minutes.
* The vehicle speed is greater than 21 km/h (13 mph).
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 center.
* 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 [1][2]Antilock Brakes / Traction Control Systems
Connector End View Reference
Component Connector End Views Hybrid/EV Battery Pack X1
Description and Operation
ABS Description and Operation Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Programming and Relearning 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.
2. Place the transmission in PARK.
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.
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.
4. Vehicle ON, apply and release the brake pedal.
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.
5. Vehicle OFF, without applying the brake pedal, remove the remote keyless entry transmitter and close all of the vehicle doors.
6. Wait approximately 1-3 minutes until the brake modulator and the high pressure accumulator pressure relief is complete and the vehicle powers down. Vehicle ON, brakes not applied
7. Verify the scan tool parameters listed below are within the specified range:
* 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 DTC C029C, C120C, C129A-C129F, C12B1, or C12F8 C029C.
• If all parameters are within the specified range
8. Vehicle ON, brakes not applied.
9. Verify the scan tool parameters listed below are less the specified range:
* 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
10. Perform a brake hydraulic check, refer to Brake Hydraulic and Assist System Diagnosis Brake Hydraulic and Assist System Diagnosis.
• If the brake hydraulic system test does not pass
Repair as necessary.
• If all parameters are less than the specified range
11. Replace the Q5 brake pressure modulator.
12. Verify the DTC does not set while operating the vehicle under the Conditions for Running the DTC.
• If the DTC sets
Replace the K17 electronic brake control module.
• If the DTC does not set
13. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Electronic Brake Control Module with Brake Pressure Modulator Valve Replacement Electronic Brake Control Module with Brake Pressure Modulator Valve Replacement
* Control Module References Programming and Relearning for electronic brake control module replacement, programming and setup