C1939 Mercury Code - Brake Pressure Switch Input Circuit Failure
Quick Answer
The C1939 diagnostic trouble code (DTC) for Mercury vehicles indicates a problem with the brake pressure switch input circuit. Common causes include Defective brake pressure switch, Damaged wiring or connectors in the brake pressure switch circuit, Low brake fluid levels. 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 Mercury indicates Brake Pressure Switch Input Circuit Failure.
- Common causes
- Common causes include Defective brake pressure switch, Damaged wiring or connectors in the brake pressure switch circuit, Low brake fluid levels.
- 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 Mercury Description
The C1939 diagnostic trouble code (DTC) for Mercury vehicles indicates a problem with the brake pressure switch input circuit. This code is typically triggered when the brake pressure switch, which is responsible for monitoring brake fluid pressure in the hydraulic system, fails to send the correct signal to the vehicle's electronic control module (ECM).
Common Causes of C1939 Mercury
- Defective brake pressure switch.
- Damaged wiring or connectors in the brake pressure switch circuit.
- Low brake fluid levels.
- Malfunctioning electronic control module (ECM).
- Corrosion or contamination in the brake pressure switch input circuit.
Symptoms of C1939 Mercury
- Illumination of the ABS or brake system warning lights on the dashboard.
- Erratic brake behavior, such as delayed braking response or reduced braking power.
- Loss of brake assist, requiring increased pedal pressure to stop the vehicle.
- Inconsistent brake pressure applied to the wheels during braking.
- Possible activation of the vehicle's limp mode to prevent further damage.
How to Fix C1939 Mercury
- Begin by conducting a thorough inspection of the brake pressure switch, wiring, and connectors to identify any visible damage or corrosion.
- Test the brake pressure switch using a multimeter to determine if it is functioning correctly.
- Check the brake fluid levels and top up if necessary, ensuring there are no leaks in the system.
- If the brake pressure switch is found to be faulty, replace it with a new, OEM-approved part.
- Clear the DTC codes from the vehicle's ECM using a diagnostic scanner and perform a test drive to confirm that the issue has been resolved.
Cost to Fix C1939 Mercury
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 in your area. On average, the parts for this repair can range from $50 to $150, while labor costs can add an additional $100 to $200. Keep in mind that diagnostic time and labor rates at auto repair shops can fluctuate, so it's advisable to obtain quotes from multiple sources to ensure a competitive price.
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Frequently Asked Questions about C1939 Mercury Code
1. What are the common symptoms of OBDII code C1939 Brake Pressure Switch Input Circuit Failure in a Mercury?
- Common symptoms include the brake warning light illuminating on the dashboard, issues with the brake system, and potential ABS malfunction.
2. What can cause the OBDII code C1939 Brake Pressure Switch Input Circuit Failure in a Mercury?
- The code can be triggered by a faulty brake pressure switch, damaged wiring in the brake pressure switch circuit, or a malfunctioning ABS module.
3. How can I diagnose the OBDII code C1939 Brake Pressure Switch Input Circuit Failure in my Mercury?
- Diagnosis typically involves using an OBDII scanner to retrieve the specific code, inspecting the brake pressure switch and its wiring for damage, and testing the ABS module for any faults.
4. Is it safe to drive my Mercury with the OBDII code C1939 Brake Pressure Switch Input Circuit Failure?
- It is not recommended to drive the vehicle with this code present, as it can affect the proper functioning of the brake system and ABS, potentially compromising safety.
5. What are some repair tips for addressing the OBDII code C1939 Brake Pressure Switch Input Circuit Failure?
- Repair tips may include replacing the faulty brake pressure switch, repairing or replacing damaged wiring, and resetting the ABS module to clear the code.
6. Can I reset the OBDII code C1939 Brake Pressure Switch Input Circuit Failure in my Mercury without fixing the underlying issue?
- While you can clear the code with an OBDII scanner, it is important to address the root cause of the problem to prevent it from recurring and ensure the safety of your vehicle.
7. How much does it typically cost to repair the OBDII code C1939 Brake Pressure Switch Input Circuit Failure in a Mercury?
- The cost of repair can vary depending on the extent of the issue, but it may involve the price of a new brake pressure switch, wiring repairs, and labor costs for diagnosis and replacement.
8. Can a DIY enthusiast fix the OBDII code C1939 Brake Pressure Switch Input Circuit Failure in a Mercury?
- While some enthusiasts may have the skills to diagnose and repair this issue, it is recommended to have a professional mechanic handle the repair due to the complexity of the brake system and ABS.
9. Will the OBDII code C1939 Brake Pressure Switch Input Circuit Failure cause my Mercury to fail an emissions test?
- The code itself may not directly impact emissions, but it is important to address the issue promptly to ensure the overall health and safety of your vehicle.
10. How long can I safely drive my Mercury with the OBDII code C1939 Brake Pressure Switch Input Circuit Failure before getting it repaired?
- It is best to avoid driving the vehicle with this code present to prevent any potential safety hazards related to brake system and ABS malfunctions.
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