OBD Guide

P1938

Brake Switch/Sensor Signal

P1938 is an OBD-II diagnostic trouble code meaning: Brake Switch/Sensor Signal. Common causes: faulty brake sensor, open or short circuit in the sensor circuit. Estimated repair cost: $6–33.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$6–33 (est.)

Symptoms

  • Cruise control doesn't work
  • Brake lights stay on or don't turn on
  • Check Engine light comes on
  • Problems with the ABS system
  • The car does not switch from parking mode

Causes

  • Faulty brake sensor
  • Open or short circuit in the sensor circuit
  • Poor contact in the sensor connector
  • Mechanical failure of the brake pedal
  • Problems with the control unit

How to Fix

  1. Check the condition of the brake sensor
  2. Inspect the wiring harness and connectors for damage.
  3. Check the voltage and resistance in the sensor circuit
  4. Replace the brake sensor if necessary
  5. Test the operation of the system after repair

Related codes

FAQ

What does the P1938 code mean?

P1938 is an OBD-II diagnostic trouble code that indicates: Brake Switch/Sensor Signal

What causes a P1938 error code?

The most common causes of P1938 include: Faulty brake sensor; Open or short circuit in the sensor circuit; Poor contact in the sensor connector; Mechanical failure of the brake pedal.

How do I fix a P1938 diagnostic trouble code?

To fix P1938: Check the condition of the brake sensor. Inspect the wiring harness and connectors for damage.. Check the voltage and resistance in the sensor circuit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P1938?

Limited driving only, diagnose soon

How much does it cost to fix P1938?

The estimated repair cost for P1938 is $6–33. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat