P1938 Mercury Code - Brake Switch/Sensor Signal
Quick Answer
The P1938 diagnostic trouble code (DTC) for Mercury vehicles relates to the brake switch/sensor signal. Common causes include Faulty brake switch/sensor, Damaged wiring or connectors in the brake switch/sensor circuit, Corrosion or dirt buildup affecting the brake switch/sensor. 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
- P1938 Mercury indicates Brake Switch/Sensor Signal.
- Common causes
- Common causes include Faulty brake switch/sensor, Damaged wiring or connectors in the brake switch/sensor circuit, Corrosion or dirt buildup affecting the brake switch/sensor.
- 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 P1938 Mercury Description
The P1938 diagnostic trouble code (DTC) for Mercury vehicles relates to the brake switch/sensor signal. This code indicates that there is a problem with the signal being sent by the brake switch or sensor to the vehicle's electronic control module (ECM). The brake switch/sensor is a crucial component in the vehicle's braking system, as it is responsible for detecting when the brake pedal is depressed and sending a signal to the ECM to activate the brake lights and other related systems.
Common Causes of P1938 Mercury
- Faulty brake switch/sensor
- Damaged wiring or connectors in the brake switch/sensor circuit
- Corrosion or dirt buildup affecting the brake switch/sensor
- ECM software issues
- Mechanical issues with the brake pedal assembly
Symptoms of P1938 Mercury
- Check engine light illuminated on the dashboard
- Non-functioning brake lights
- Inoperative cruise control system
- Traction control system malfunctions
- Difficulty shifting out of park (in some cases)
How to Fix P1938 Mercury
- Begin by conducting a visual inspection of the brake switch/sensor, wiring, and connectors to check for any visible damage or corrosion.
- Use a multimeter to test the continuity and voltage of the brake switch/sensor to determine if it is functioning correctly.
- If the brake switch/sensor is faulty, replace it with a new OEM or high-quality aftermarket part.
- Clear the DTC using an OBD-II scanner and test drive the vehicle to ensure that the code does not reappear.
- If the issue persists, further diagnostics may be necessary to identify any underlying wiring or ECM problems.
Cost to Fix P1938 Mercury
The cost of repairing the P1938 code related to the brake switch/sensor signal 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 the labor costs can be between $100 and $200. Keep in mind that additional diagnostic time may be needed if there are underlying wiring or ECM issues. It is advisable to consult with a trusted mechanic or auto repair shop to get an accurate estimate based on your vehicle's make and model.
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Frequently Asked Questions about P1938 Mercury Code
1. What does the OBDII code P1938 mean on a Mercury vehicle?
P1938 indicates an issue with the brake switch or sensor signal in the vehicle, which can affect the brake light operation and potentially the shift interlock system.
2. What are the common symptoms of code P1938 in a Mercury?
Symptoms may include non-functional brake lights, the inability to shift from park, or a warning light on the dashboard.
3. What causes the P1938 code to appear?
The most common causes are a faulty brake light switch, damaged wiring or connectors in the brake switch circuit, or a malfunctioning brake pedal position sensor.
4. Can I drive my Mercury with the P1938 code active?
Driving with this code is possible but not recommended, as it may cause safety issues like non-functioning brake lights or difficulties shifting out of park.
5. How do I diagnose the P1938 code on my Mercury?
Start by checking the brake lights for proper operation, inspecting the brake switch and its wiring for damage, and using a multimeter to test the brake switch's functionality.
6. How do I fix the P1938 code on a Mercury?
Repairs may involve replacing a faulty brake light switch, repairing damaged wiring, or recalibrating or replacing the brake pedal position sensor.
7. Is the P1938 code specific to Mercury vehicles?
While the code can appear on other makes, the specifics of the issue and repair process may vary depending on the Mercury model and year.
8. How much does it cost to fix the P1938 code on a Mercury?
Repair costs can range from $50 to $200, depending on whether the brake switch or sensor needs replacement or if wiring repairs are required.
9. Can the P1938 code trigger other issues in my Mercury?
Yes, it can affect systems like the cruise control, shift interlock, and anti-lock braking system (ABS), depending on the severity of the brake switch or sensor failure.
10. Will clearing the P1938 code fix the problem permanently?
Clearing the code without addressing the root cause will not resolve the issue, and the code is likely to return. Proper diagnosis and repair are essential.
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