Fault code C1500 – a step-by-step guide to diagnosing and fixing it

Error code C1500 is displayed and the check engine light is on - what does this mean?

The DTC C1500 is recognized by the OBD system and indicates a fault in the anti-lock braking system (ABS), specifically a fault in the left front wheel speed sensor or its signal circuit. This trouble code may have slightly different names for different manufacturers, but basically refers to the ABS sensors on the front axle.

What causes can this fault code have?

• Defective left front wheel speed sensor
• Damaged or interrupted sensor cable
• Corroded or loose plug connections on the ABS sensor
• Dirty or damaged sensor ring on the wheel
• Defective ABS control unit
• Mechanical damage to the sensor bracket
• Excessive air gap between sensor and pulse ring
• Short circuit in the sensor wiring

What symptoms occur in parallel with fault code C1500?

• ABS warning light: The ABS indicator light in the dashboard lights up continuously
• ESP/ASR malfunction: Electronic stability programs no longer work
• Braking problems: ABS function is deactivated, normal braking is maintained
• Unusual braking noises: squealing or grinding possible when braking
• Vehicle diagnostics: EOBD scanner displays additional ABS-related fault codes

How to fix the problem of fault code C1500?

• Repairing fault code C1500 requires a systematic approach to identify the exact cause.
• Sensor cleaning and adjustment: Thoroughly clean the left front ABS sensor to remove dirt and metal shavings, check the correct distance to the pulse ring (usually 0.5-2mm) and readjust the position if necessary
• Cable check and repair: Check the entire sensor cable for damage, breaks or chafing, repair defective areas or replace the entire cable in the event of severe damage
• Repair plug connections: Disconnect all plug connections of the ABS sensor, clean the contacts with contact cleaner, treat them with contact spray and ensure firm, corrosion-free connections
• Replace the sensor: Remove the defective left front wheel speed sensor, install a new OEM-compatible sensor and carry out a basic adjustment using a suitable diagnostic device
• Replace the pulse ring: Check the sensor ring for damage or missing teeth, replace it if it is defective and ensure that it is mounted correctly and that the surface is clean