C129B Code - Brake Pedal Position Sensor 3 Circuit High Input
Quick Answer
The Electronic Brake Control Module (EBCM) uses inputs from the electronic brake control brake pedal position sensor to determine when the brake is applied and how much force is used. Common causes include Faulty Brake Pedal Position Sensor, Brake Pedal Position Sensor harness is open or shorted, Brake Pedal Position Sensor circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- C129B indicates Brake Pedal Position Sensor 3 Circuit High Input.
- Common causes
- Common causes include Faulty Brake Pedal Position Sensor, Brake Pedal Position Sensor harness is open or shorted, Brake Pedal Position Sensor circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code C129B Description
What are the Possible Causes of the DTC C129B?
- Faulty Brake Pedal Position Sensor
- Brake Pedal Position Sensor harness is open or shorted
- Brake Pedal Position Sensor circuit poor electrical connection
- Faulty Electronic Brake Control Module (EBCM)
How to Fix the DTC C129B?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the C129B code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the C129B code?
Need more information on how to fix the C129B code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the C129B code diagnosed by a professional: Find a repair shop in your area
Information for Specific Makes
- C129B Buick — Brake Pedal Position Sensor 3 Circuit High Input
- C129B Cadillac — Brake Pedal Position Sensor 3 Circuit High Input
- C129B Chevrolet — Brake Pedal Position Sensor 3 Circuit High Input
- C129B GMC — Brake Pedal Position Sensor 3 Circuit High Input
Frequently Asked Questions about C129B Code
1. What does the OBDII code C129B mean?
C129B indicates a high input signal from Brake Pedal Position Sensor 3, suggesting an issue with the sensor's circuit or related components.
2. What are the symptoms of code C129B?
Common symptoms include the ABS or traction control light illuminating, difficulty disengaging cruise control, or inconsistent brake light operation.
3. What causes the C129B code to appear?
Causes can include a faulty brake pedal position sensor, damaged wiring or connectors, or an issue with the vehicle's electronic control module (ECM).
4. Is it safe to drive with code C129B?
It may be unsafe, as the issue can affect braking-related systems like ABS or traction control. Prompt diagnosis and repair are recommended.
5. How is code C129B diagnosed?
A technician will inspect the brake pedal position sensor, check the wiring and connectors for damage, and use a scan tool to verify the sensor's signal and voltage.
6. Can I fix the C129B code myself?
If you're experienced with car repairs, you can inspect the brake pedal position sensor and wiring, but professional diagnosis is recommended for accuracy.
7. How much does it cost to repair code C129B?
Repair costs vary but typically range from $100 to $300, depending on whether the sensor, wiring, or ECM requires repair or replacement.
8. What tools are needed to fix the C129B code?
Common tools include a scan tool, multimeter for voltage testing, and basic hand tools to inspect and replace the sensor or wiring.
9. Can a dead battery cause code C129B?
Unlikely, but a weak or unstable power supply can sometimes lead to errors in electronic systems, so checking the battery is still a good idea.
10. How can I prevent code C129B from occurring?
Regularly inspect electrical connections, keep the brake system well-maintained, and address any brake-related warning lights promptly.
Discuss the causes and fixes for C129B OBDII Code
Code C129B comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
