Fault code C1200 – a step-by-step guide to diagnosing and fixing it

Error code C1200 is displayed and the check engine light is on - what does this mean?

The DTC C1200 is recognized by the OBD system and indicates a fault in the ABS system, more specifically a defect in the hydraulic pump or the hydraulic circuit. This trouble code mainly concerns the anti-lock braking system and may have slightly different definitions for different manufacturers, but basically refers to hydraulic problems in the brake system.

What causes can this fault code have?

• Defective ABS hydraulic pump
• Blocked hydraulic lines in the ABS system
• Low brake fluid level
• Damaged plug connections on the ABS control unit
• Defective ABS control unit
• Worn seals in the hydraulic unit
• Corrosion in the brake lines
• Defective pressure sensors in the ABS system

What symptoms occur in parallel with fault code C1200?

• ABS warning light illuminates: The ABS symbol in the dashboard is permanently activated
• Brake pedal feel changed: The pedal feels spongy or hard
• Increased braking distances: The vehicle needs more distance to stop
• Pumping noises: Unusual noises from the engine compartment when braking
• ESP/ESC malfunction: Other driver assistance systems may be affected
• Brake booster problems: Increased effort required when braking

How can the fault code C1200 problem be rectified?

• Repairing fault code C1200 requires a systematic approach and should preferably be carried out by a specialist workshop.
• Check and top up the brake fluid level: Check the level in the brake fluid reservoir and top up with the brake fluid specified by the manufacturer if necessary, then bleed the entire brake system
• Check ABS control unit and wiring: Test all electrical connections to the ABS module with a multimeter, clean corroded contacts and replace damaged cables or connectors
• Replace hydraulic pump: Dismantle the defective ABS hydraulic pump, install a new or reconditioned unit and perform a complete system calibration
• Replace pressure sensors in the ABS system: Locate the defective pressure sensors using diagnostic equipment, remove them and install new sensors followed by system initialization
• Replace the entire ABS unit: If the damage is severe, replace the entire ABS/ESP hydraulic unit, program the new control unit and perform a basic adjustment of all systems