OBD Guide

C1237

Speed Wheel Rear Input Signal Missing

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$33–111 (est.)

Symptoms

  • ABS/ESP indicator is on
  • Disabling the ABS/ESP system
  • Incorrect operation of cruise control (if equipped)

Causes

  • Rear wheel speed sensor malfunction
  • Open or short circuit in wiring harness
  • Impulse rotor is dirty or damaged
  • Poor contact in the sensor connector
  • ABS/ESP module malfunction

How to Fix

  1. Check the integrity of the sensor wiring harness
  2. Clean the contacts of the sensor connector
  3. Check the resistance of the wheel speed sensor
  4. Inspect the impulse rotor for damage
  5. If necessary, replace the wheel speed sensor

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