Code Definition

P0551 — Power Steering Pressure Sensor Circuit Range/Performance

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0551

P0551 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0551 is stored, the module has detected a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P0551 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The P0551 fault code is set when the Engine Control Module (ECM) detects that the range or performance of the power steering pressure sensor is outside the expected parameters. This sensor is a key component in the power steering system, measuring the hydraulic pressure and relaying this information to the ECM. The ECM uses these data to adjust the power steering assist level for optimal steering response and effort. Deviations in the sensor's range or performance can lead to steering issues such as inconsistent power assist, harder steering effort, or activation of power steering warning indi...

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