C0139 GMC Code - Base Brake System Pressure Circuit/Sensor High
Quick Answer
The C0139 diagnostic trouble code (DTC) indicates a problem with the base brake system pressure circuit or sensor, specifically that the signal is reading higher than expected. Common causes include Faulty Brake Pressure Sensor: A malfunctioning or damaged brake pressure sensor can send incorrect readings to the ECU, Wiring Issues: Damaged or corroded wiring and connectors in the brake pressure circuit can lead to high resistance or short circuits, Hydraulic System Problems: Leaks or blockages in the brake hydraulic system can cause abnormal pressure readings. 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
- C0139 GMC indicates Base Brake System Pressure Circuit/Sensor High.
- Common causes
- Common causes include Faulty Brake Pressure Sensor: A malfunctioning or damaged brake pressure sensor can send incorrect readings to the ECU, Wiring Issues: Damaged or corroded wiring and connectors in the brake pressure circuit can lead to high resistance or short circuits, Hydraulic System Problems: Leaks or blockages in the brake hydraulic system can cause abnormal pressure readings.
- 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.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
Code C0139 GMC Description
The C0139 diagnostic trouble code (DTC) indicates a problem with the base brake system pressure circuit or sensor, specifically that the signal is reading higher than expected. This code is prevalent in GMC vehicles and is related to the brake system's hydraulic pressure monitoring. The brake pressure sensor is responsible for measuring the hydraulic pressure in the brake system and relaying this information to the vehicle's electronic control unit (ECU). When the ECU detects that the pressure reading exceeds the predetermined threshold, it triggers the C0139 code.
Common Causes of C0139 GMC
- Faulty Brake Pressure Sensor: A malfunctioning or damaged brake pressure sensor can send incorrect readings to the ECU.
- Wiring Issues: Damaged or corroded wiring and connectors in the brake pressure circuit can lead to high resistance or short circuits.
- Hydraulic System Problems: Leaks or blockages in the brake hydraulic system can cause abnormal pressure readings.
- Faulty ECU: In rare cases, a malfunctioning ECU may misinterpret sensor data, triggering the C0139 code.
- Brake Fluid Contamination: Contaminated brake fluid can affect the performance of the brake system and lead to sensor inaccuracies.
Symptoms of C0139 GMC
- Warning Light: The brake warning light may illuminate on the dashboard, indicating a problem with the brake system.
- Erratic Braking: Drivers may experience inconsistent braking performance, such as delayed response or sudden changes in braking force.
- Increased Stopping Distance: The vehicle may require a longer distance to come to a complete stop, compromising safety.
- Brake Pedal Feel: The brake pedal may feel spongy or overly firm, indicating issues with brake pressure regulation.
- ABS Activation: The anti-lock braking system (ABS) may activate unexpectedly or fail to engage during hard braking situations.
How to Fix C0139 GMC
- Diagnostic Scan: Begin by using an OBD-II scanner to confirm the C0139 code and check for any additional codes that may provide further insight into the issue.
- Visual Inspection: Inspect the brake pressure sensor, wiring, and connectors for any signs of damage, corrosion, or loose connections.
- Test the Brake Pressure Sensor: Using a multimeter, test the brake pressure sensor's resistance and voltage output to ensure it operates within the manufacturer's specifications.
- Check the Hydraulic System: Inspect the brake lines, master cylinder, and calipers for leaks or blockages that could affect pressure readings.
- Replace Faulty Components: If any faulty components are identified, such as the brake pressure sensor or damaged wiring, replace them and clear the DTC from the ECU.
Cost to Fix C0139 GMC
The cost to repair the C0139 code can vary widely based on the specific diagnosis and required repairs. On average, the total cost may range from $150 to $800. This estimate includes parts and labor, with parts such as a brake pressure sensor typically costing between $50 and $200. Labor costs can vary significantly depending on location and the complexity of the repair, with most auto repair shops charging between $80 and $150 per hour. In metropolitan areas or at dealerships, rates may be higher, while independent shops may offer lower rates. It is advisable to check local rates and obtain multiple quotes for a more precise estimate.
Need more information about the C0139 GMC code?
Need more information on how to fix the C0139 GMC code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the C0139 GMC code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about C0139 GMC Code
1. What are the common symptoms of OBDII code C0139 GMC?
- Common symptoms include the illumination of the ABS warning light on the dashboard, potential loss of traction control, and possible issues with the vehicle's braking system.
2. What can cause OBDII code C0139 GMC to trigger?
- This code is typically triggered by a high pressure reading in the base brake system, which may be caused by a malfunctioning brake pressure sensor or issues with the brake system hydraulics.
3. How serious is OBDII code C0139 GMC?
- This code indicates a problem with the base brake system pressure circuit/sensor, which can affect the vehicle's braking performance and safety. It is important to address this issue promptly.
4. What are some repair tips for OBDII code C0139 GMC?
- Repair tips may include checking and recalibrating the brake pressure sensor, inspecting the brake system for any leaks or malfunctions, and ensuring proper brake fluid levels.
5. Can I continue driving with OBDII code C0139 GMC illuminated?
- It is not recommended to continue driving with this code illuminated, as it may indicate a potential issue with the vehicle's braking system that could compromise safety.
6. How can I diagnose OBDII code C0139 GMC?
- Diagnosis typically involves using a scan tool to read the code, checking the brake pressure sensor for proper operation, inspecting the brake system for leaks or damage, and performing necessary repairs.
7. Is OBDII code C0139 GMC a common issue in GMC vehicles?
- While this code may not be as common as some other OBDII codes, it can still occur in GMC vehicles with ABS and traction control systems.
8. Can weather conditions affect the triggering of OBDII code C0139 GMC?
- Extreme weather conditions, such as very high or very low temperatures, can potentially affect the operation of the brake pressure sensor and trigger this code.
9. How much does it typically cost to repair OBDII code C0139 GMC?
- The cost of repairing this code can vary depending on the specific cause of the issue, but it may involve sensor recalibration, brake system repairs, or sensor replacement, which can range from moderate to expensive.
10. Will resetting the OBDII code C0139 GMC make it go away permanently?
- Simply resetting the code without addressing the underlying issue will not make it go away permanently. It is important to diagnose and repair the root cause of the problem to prevent the code from reoccurring.
Discuss the causes and fixes for C0139 GMC OBDII Code
Code C0139 GMC 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.