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P0551 – Power Steering Pressure Sensor Circuit Range/Performance (OBD2)

P0551 means "Power Steering Pressure Sensor Circuit Range/Performance". The power steering pressure sensor / control signal is electrically present but implausible: it does not match what the control unit expects for the current operating conditions or from other sensors. This is a performance fault, not a broken wire.

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P0551 quick summary

Fault codeP0551
MeaningPower Steering Pressure Sensor Circuit Range/Performance
SystemPowertrain (Engine & Transmission)
VehiclesGeneric OBD2
SeverityLow
Can I drive?Yes. Be careful when manoeuvring at low speed, as the engine may stall.
Repair cost€20 – €300

How power steering signals are used by the engine

The engine control unit monitors power steering pressure or controls power steering assistance, so it can raise the idle when steering at standstill; these codes cover the sensor and control circuits.

On cars with hydraulic power steering, a pressure sensor or switch tells the engine control unit when the pump is working hard (for example when turning the wheel at standstill), so it can raise the idle to prevent stalling. Some systems also have an electrically controlled steering assistance valve.

Codes P0550–P0554 report faults in the power steering pressure sensor circuit; P0635–P0637 in the power steering control circuit.

A faulty signal may cause the engine to stall or the idle to dip when manoeuvring. Steering assistance itself usually still works on hydraulic systems.

On VAG vehicles (VW, Audi, Škoda, Seat, Cupra), VCDS and older VAG testers can show this code as the five-digit VAG code 16935 (P0551). Both numbers mean the same fault.

Symptoms of P0551

  • Engine stalls or idle dips when turning the wheel at standstill
  • Check Engine light on
  • Steering feels heavier (control circuit faults)
  • Power steering fluid leak near the sensor
  • Often no other symptoms

Most common causes of P0551 (most likely first)

Mechanic's Pro Tip

Power steering pressure switches often leak fluid into their own connector – clean the connector when replacing the sensor.

  1. 1.Power steering pressure sensor / control worn, contaminated or out of calibration

    Most likely

    The signal drifts slowly, so it is still within the electrical limits but wrong.

  2. 2.Mechanical problem in the system the power steering pressure sensor / control measures or controls

    For example a leak, a sticking part or a restriction that really changes the measured value.

  3. 3.High resistance in a connector or ground

    Corrosion causes a voltage drop that shifts the reading.

  4. 4.Faulty power steering pressure sensor or switch

  5. 5.Fluid leak at the sensor

  6. 6.Low power steering fluid

  7. 7.Control valve or module fault

Step-by-step diagnostic guide

  1. 1

    Read codes and check fluid

    Read all codes and check the power steering fluid level.

  2. 2

    Compare live data with expected values

    Read the power steering pressure sensor / control values in live data and compare them with related readings (engine speed, load, temperature or pressure) and with the specification. A value that is electrically fine but wrong for the conditions confirms a performance fault – then check the mechanical side before replacing the part.

  3. 3

    Watch the sensor signal

    Watch the sensor value in live data while turning the wheel at standstill – it must change.

  4. 4

    Check the sensor wiring

    Check the connector and wiring for damage and fluid contamination.

  5. 5

    Measure the sensor

    Check the supply and signal according to the specification.

  6. 6

    Replace and verify

    Replace the sensor, top up fluid and check that the idle stays stable when steering.

Frequently asked questions

Can I keep driving with P0551?

Yes. Be careful when manoeuvring at low speed, as the engine may stall.

How much does it cost to fix P0551?

Typical repair costs are 20 € – 300 €, depending on the cause and the vehicle. The most common fixes are: power steering pressure sensor / control worn, contaminated or out of calibration; mechanical problem in the system the power steering pressure sensor / control measures or controls; high resistance in a connector or ground. Always confirm the cause with the tests above before buying parts.

Does the code affect the steering?

On hydraulic systems usually not; it mainly affects idle control. Control circuit faults can reduce assistance.

Why does the engine stall when I turn the wheel?

The pump loads the engine. If the control unit does not know, it does not raise the idle in time.

What is the difference between P0551 and similar codes?

P0551 belongs to a group of codes for the same component that differ in the type or location of the fault: P0550 – Power Steering Pressure Sensor Circuit Malfunction; P0552 – Power Steering Pressure Sensor Circuit Low Input; P0553 – Power Steering Pressure Sensor Circuit High Input; P0554 – Power Steering Pressure sensor Circuit Intermittent; P0635 – Power Steering Control Circuit; P0636 – Power Steering Control Circuit Low. The tests on this page apply to the whole group; the type of fault tells you where to start.

Related fault codes

This guide is for information only. Working on vehicles can be dangerous — if you are unsure, have the car checked by a qualified mechanic. Values can differ between model years; always check the manufacturer's repair information.