C1238 – BMW DTC

BMW DTC C1238 – Right Rear Wheel Speed Sensor Signal Implausible

DTC C1238 meaning on BMW

DTC C1238 on a BMW indicates an issue with the right rear wheel speed sensor signal being implausible. This means that the signal being received from the right rear wheel speed sensor does not align with the expected values, leading to a fault code being triggered in the vehicle’s system.

BMW DTC C1238 symptoms

Symptoms of DTC C1238 on a BMW may include:

  • ABS warning light illuminated on the dashboard
  • Traction control system malfunction
  • Unusual braking behavior, such as ABS activation under normal braking conditions
  • Loss of stability control

BMW DTC C1238 causes

Common causes of DTC C1238 on a BMW include:

  • Failed right rear wheel speed sensor
  • Damaged or corroded sensor wiring or connectors
  • Faulty ABS control module
  • Issues with the tone ring or reluctor wheel

BMW DTC C1238 seriousness

DTC C1238 should be taken seriously as it can affect the proper functioning of the vehicle’s ABS and stability control systems. Driving with this fault unresolved may compromise the safety and stability of the vehicle, especially during emergency braking or slippery road conditions.

How to diagnose DTC C1238 on BMW

To diagnose DTC C1238 on a BMW, you can perform the following steps:

  1. Use a diagnostic scanner to retrieve the fault codes from the vehicle’s ABS system
  2. Inspect the right rear wheel speed sensor for any visible damage or contamination
  3. Check the sensor wiring and connectors for signs of wear, corrosion, or disconnection
  4. Test the sensor’s output signal using a multimeter to verify its functionality
  5. Inspect the tone ring or reluctor wheel for damage or missing teeth

How to fix DTC C1238 on BMW

To fix DTC C1238 on a BMW, you can try the following solutions:

  1. Replace the right rear wheel speed sensor if it is found to be faulty
  2. Repair or replace any damaged sensor wiring or connectors
  3. Check and clean the tone ring or reluctor wheel to ensure proper sensor operation
  4. If the issue persists, consider diagnosing the ABS control module for potential faults

How to erase DTC C1238 on BMW

To erase DTC C1238 on a BMW, you can use a diagnostic scanner to clear the fault codes stored in the vehicle’s ABS system. After performing the necessary repairs or replacements, you can reset the system to see if the fault code reoccurs. If the issue has been successfully resolved, the fault code should not return upon driving the vehicle.

Recommended tools & DTC Scanners for BMW

Best Diagnostic App for modern BMWs: BimmerLink

Recommended Bluetooth adapter for Bimmerlink: OBDLink CX

Cable adapter for Bimmerlink: Enet Cable USB Type C

For older BMWs we recommend: Autel AutoLink AL319 (2024 version)

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

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