C1939 Code - Brake Pressure Switch Input Circuit Failure
Quick Answer
The diagnostic trouble code C1939 indicates a Brake Pressure Switch Input Circuit Failure. Common causes include Damaged wiring or connectors in the brake pressure switch input circuit, Faulty brake pressure switch, Malfunctioning electronic control unit (ECU). 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
- C1939 indicates Brake Pressure Switch Input Circuit Failure.
- Common causes
- Common causes include Damaged wiring or connectors in the brake pressure switch input circuit, Faulty brake pressure switch, Malfunctioning electronic control unit (ECU).
- 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.
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Code C1939 Description
The diagnostic trouble code C1939 indicates a Brake Pressure Switch Input Circuit Failure. This means that there is a malfunction in the brake pressure switch input circuit, which is a crucial component in the vehicle's braking system. The brake pressure switch is responsible for monitoring the brake fluid pressure in the hydraulic system and sending this information to the vehicle's electronic control unit (ECU). If the ECU detects a failure in the brake pressure switch input circuit, it may illuminate the check engine light and affect the vehicle's braking performance.
Common Causes of C1939
- Damaged wiring or connectors in the brake pressure switch input circuit
- Faulty brake pressure switch
- Malfunctioning electronic control unit (ECU)
- Corrosion in the circuit connections
- Low brake fluid levels
Symptoms of C1939
- Illumination of the check engine light
- Soft or spongy brake pedal
- Difficulty stopping the vehicle
- ABS system malfunction
- Brake fluid leaks
How to Fix C1939
- Diagnose the issue by using a scan tool to retrieve the trouble code and inspect the brake pressure switch input circuit.
- Inspect the wiring and connectors for any damage or corrosion and repair or replace as necessary.
- Test the brake pressure switch for proper operation and replace if faulty.
- Clear the trouble code from the ECU's memory and test drive the vehicle to ensure the issue has been resolved.
- If the problem persists, further diagnostics may be required to pinpoint the exact cause of the failure.
Cost to Fix C1939
The cost of repairing a Brake Pressure Switch Input Circuit Failure can vary depending on the specific cause of the issue and the labor rates at the auto repair shop. On average, the repair cost for this type of issue can range from $150 to $400, including parts and labor. It's important to note that the actual cost may be higher or lower based on the severity of the problem and the need for additional repairs. It's recommended to consult with a qualified mechanic to get an accurate estimate for your specific vehicle.
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Code C1939 Information for Specific Makes
- C1939 Ford — Brake Pressure Switch Input Circuit Failure
- C1939 Lexus — Front Boosted Voltage
- C1939 Lincoln — Brake Pressure Switch Input Circuit Failure
- C1939 Mercury — Brake Pressure Switch Input Circuit Failure
- C1939 Toyota — Front Boosted Voltage
Frequently Asked Questions about C1939 Code
1. What are the common symptoms of OBDII code C1939 (Brake Pressure Switch Input Circuit Failure)?
- Common symptoms include the illumination of the "Brake Warning Light" on the dashboard, issues with the brake system, and potential loss of brake functionality.
2. What are the possible causes of OBDII code C1939?
- The code C1939 can be caused by a faulty brake pressure switch, damaged wiring or connectors in the brake pressure switch circuit, or a malfunctioning brake control module.
3. How serious is the OBDII code C1939 (Brake Pressure Switch Input Circuit Failure)?
- The code C1939 is a serious issue as it directly impacts the proper functioning of the brake system, potentially compromising vehicle safety. It is important to address this code promptly.
4. How can I diagnose OBDII code C1939?
- Diagnosing OBDII code C1939 involves using a diagnostic scanner to retrieve the code, conducting a visual inspection of the brake pressure switch and its wiring, and testing the switch for proper functionality.
5. Is it safe to drive with OBDII code C1939 active?
- It is not recommended to drive with OBDII code C1939 active, as it indicates a potential failure in the brake pressure switch circuit, which can lead to brake-related issues and compromise safety.
6. How can I repair OBDII code C1939?
- Repairing OBDII code C1939 involves replacing the faulty brake pressure switch, repairing or replacing damaged wiring or connectors, and clearing the fault code with a diagnostic scanner.
7. Can I reset OBDII code C1939 without fixing the underlying issue?
- While you can clear the fault code temporarily, it is important to address the underlying issue causing OBDII code C1939 to prevent potential safety hazards and ensure the proper functioning of the brake system.
8. Are there any DIY tips for troubleshooting OBDII code C1939?
- DIY tips for troubleshooting OBDII code C1939 include checking the brake fluid level, inspecting the brake pressure switch for visible damage, and ensuring all brake system components are properly connected.
9. How much does it cost to repair OBDII code C1939 at a mechanic or dealership?
- The cost of repairing OBDII code C1939 can vary depending on the specific cause of the issue, but it generally ranges from $100 to $300 for parts and labor at a mechanic or dealership.
10. Can OBDII code C1939 be prevented?
- While some causes of OBDII code C1939 may be unavoidable, regular maintenance of the brake system, including checking brake fluid levels and inspecting brake components, can help prevent issues that trigger this code.
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