P1938 Lincoln Code - Brake Switch/Sensor Signal
Quick Answer
The P1938 diagnostic trouble code (DTC) is specific to Lincoln vehicles and indicates an issue with the brake switch or sensor signal. Common causes include Faulty Brake Switch: The most common cause is a malfunctioning brake switch that fails to send the correct signal, Wiring Issues: Damaged or corroded wiring in the brake switch circuit can disrupt the signal to the ECM, Connector Problems: Loose or corroded connectors can lead to intermittent signals, triggering the code. 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 Lincoln indicates Brake Switch/Sensor Signal.
- Common causes
- Common causes include Faulty Brake Switch: The most common cause is a malfunctioning brake switch that fails to send the correct signal, Wiring Issues: Damaged or corroded wiring in the brake switch circuit can disrupt the signal to the ECM, Connector Problems: Loose or corroded connectors can lead to intermittent signals, triggering the code.
- 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 Lincoln Description
The P1938 diagnostic trouble code (DTC) is specific to Lincoln vehicles and indicates an issue with the brake switch or sensor signal. This code is triggered when the Engine Control Module (ECM) detects an abnormal signal from the brake switch, which is responsible for communicating the status of the brake pedal to various vehicle systems. The brake switch plays a crucial role in the vehicle's safety and operational systems, including the anti-lock braking system (ABS), traction control, and cruise control.
Common Causes of P1938 Lincoln
- Faulty Brake Switch: The most common cause is a malfunctioning brake switch that fails to send the correct signal.
- Wiring Issues: Damaged or corroded wiring in the brake switch circuit can disrupt the signal to the ECM.
- Connector Problems: Loose or corroded connectors can lead to intermittent signals, triggering the code.
- ECM Malfunction: In rare cases, the ECM itself may be faulty and misinterpreting the signals from the brake switch.
- Environmental Factors: Moisture or debris entering the brake switch assembly can lead to corrosion and failure.
Symptoms of P1938 Lincoln
- Cruise Control Malfunction: The cruise control may not engage or disengage properly, leading to unsafe driving conditions.
- Warning Lights: The brake warning light or other related warning lights may illuminate on the dashboard.
- Inconsistent Brake Response: Drivers may experience inconsistent braking performance, where the brakes may feel unresponsive or overly sensitive.
- ABS Issues: The anti-lock braking system may fail to activate during hard braking, increasing the risk of skidding.
- Electrical Problems: Other electrical components may exhibit erratic behavior due to the faulty signal, such as dashboard lights flickering.
How to Fix P1938 Lincoln
- Diagnostic Scan: Start by using an OBD-II scanner to confirm the P1938 code and check for any related codes that may provide additional context.
- Visual Inspection: Conduct a thorough visual inspection of the brake switch, wiring, and connectors for signs of damage, corrosion, or loose connections.
- Test the Brake Switch: Use a multimeter to test the brake switch for continuity and proper operation. If the switch is faulty, it will need to be replaced.
- Repair Wiring/Connectors: If any wiring or connectors are found to be damaged, repair or replace them as necessary to ensure a solid electrical connection.
- Clear Codes and Test Drive: After repairs, clear the DTCs using the scanner, then perform a test drive to ensure the issue is resolved and the code does not reappear.
Cost to Fix P1938 Lincoln
** The typical cost to diagnose and repair a P1938 code can range from $100 to $400, depending on the specific issue identified. This estimate includes parts and labor. For instance, a new brake switch may cost between $30 and $100, while labor costs can vary widely. Most auto repair shops charge between $80 and $150 per hour; however, rates in metropolitan areas or at dealerships may be higher, while independent shops often charge less. It's advisable to check local rates for a more precise estimate. Additionally, the diagnosis time may vary based on the complexity of the issue and the technician's experience.
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