Fault code P0551 – a step-by-step guide to diagnosing and fixing it

Error code P0551 is displayed and the check engine light is on - what does this mean?

The OBD/EOBD system has detected a fault in the power steering system, more precisely a fault in the power steering pressure sensor or its circuit. This DTC P0551 indicates a problem with the pressure measurement in the power steering system, which means that the engine control system cannot respond correctly to the steering effort.

What can cause this error code?

• Defective power steering pressure sensor
• Damaged cable connections to the pressure sensor
• Corroded or loose plug connections
• Defective power steering pump
• Low power steering fluid level
• Clogged power steering filter
• Faulty engine control unit (ECU)
• Damaged pressure lines in the steering system

What symptoms occur in parallel with fault code P0551?

• Sluggish steering: The steering wheel is harder to turn, especially at low speeds or when parking. Irregular steering assistance: The power steering works unevenly or fails intermittently. Engine idling problems: The engine may run rough or the engine speed may fluctuate when steering. Whistling noises: Unusual noises from the engine compartment when steering. Increased fuel consumption: The engine has to work harder to compensate for the lack of steering assistance.

How to fix the problem of error code P0551?

• The repair requires a systematic diagnosis of the power steering system to identify the exact cause.
• Check and top up the power steering fluid: Check the fluid level in the power steering reservoir and top up with the correct hydraulic fluid if necessary
• Replace pressure sensor: Replace the defective power steering pressure sensor with a new original part and reprogram the control unit
• Repair cable connections: Check all cables to the pressure sensor for damage and repair or replace defective cables
• Clean plug connections: Remove corrosion from electrical connections and restore secure contact
• Replace power steering pump: If the pump is defective, carry out a complete replacement and bleed the system
• Replace hydraulic filter: Replace clogged filters in the power steering system and flush the system