Fault code C1111 – a step-by-step guide to diagnosing and fixing it

Error code C1111 is displayed and the check engine light is on - what does this mean?

The DTC C1111 is recognized by the OBD/EOBD system and indicates a problem in the ABS control module or the communication between different control units. This error code mainly affects the anti-lock braking system and can have slightly different meanings for different manufacturers, but generally refers to communication errors or control unit faults.

What causes can this error code have?

• Defective ABS control unit
• Damaged cable connections to the ABS module
• Corroded or loose plug connections
• Faulty CAN bus communication
• Defective wheel speed sensors
• Power supply problems in the ABS system
• Software error in the control unit
• Damaged fuses in the ABS circuit

What symptoms occur in parallel with fault code C1111?

• ABS warning light: The ABS indicator light is permanently illuminated in the dashboard
• Braking problems: Extended braking distances or locking wheels when braking
• ESP malfunction: The Electronic Stability Program is not working properly
• Starting problems: In rare cases, difficulty starting the engine
• Other warning lights: Additional indicator lights may light up
• Reduced driving stability: Especially in wet or slippery road conditions

How to fix the problem of error code C1111?

• The repair of error code C1111 requires a systematic approach and should be carried out by a specialist workshop.
• Check the ABS control unit and replace if necessary: Replace the defective control module with a new or reconditioned spare part and have it reprogrammed
• Check and repair cable connections: Check all cables to the ABS system for damage and replace or repair defective cables
• Clean and secure plug connections: Clean corroded contacts, treat with contact spray and tighten all connections firmly
• Replace wheel speed sensors: Identify defective sensors on the wheels and replace with new original parts
• Diagnose the CAN bus system: Check the entire network communication between the control units and replace faulty components
• Check fuses and relays: Check all relevant fuses in the ABS system and replace if necessary
• Carry out software update: Update the ABS control unit with the latest firmware to eliminate known software errors