Description of the P0551 fault code.
OBD2 Error Codes

P0551 Power Steering Pressure Sensor Circuit Signal Out of Performance Range

26.05.2022 /

P0551 – OBD-II Trouble Code Technical Description

Trouble code P0551 indicates a problem with the power steering pressure sensor.

What does the fault code mean P0551?

Trouble code P0551 indicates a problem with the power steering pressure sensor. This means that the engine control module (PCM) received an incorrect voltage input from this sensor. In most cases, this problem occurs when the car is driven at low engine speeds. When this error occurs, the check engine light on your vehicle's dashboard will illuminate and a P0551 error will be displayed.

Fault code P0551.

Possible reasons

Some possible reasons for the P0551 trouble code:

  • Faulty oil pressure sensor: The power steering pressure sensor may be damaged or fail, causing an incorrect signal to be sent to the PCM.
  • Wiring problems: The wires connecting the pressure sensor to the PCM may be open, damaged, or have poor connections, resulting in an incorrect signal.
  • Connector problems: The connectors connecting the pressure sensor to the wires or PCM may be oxidized or damaged, interfering with signal transmission.
  • Low oil level in the power steering system: Insufficient oil level may cause the pressure sensor to malfunction.
  • Power steering problems: Some problems with the power steering device itself can cause the P0551 code.
  • Problems with PCM: In rare cases, improper PCM operation may be the cause of P0551.

These are just some of the possible reasons. For an accurate diagnosis, it is recommended to contact a qualified auto mechanic or car service center.

What are the symptoms of a fault code? P0551?

Symptoms for DTC P0551 may include the following:

  • Changes in power steering operation: There may be a change in the level of force required to turn the steering wheel. This may result in the steering becoming heavier or, conversely, lighter than usual.
  • Unusual sounds from the power steering system: You may hear knocking, squeaking, or other unusual noises when turning the steering wheel, which may indicate a problem with your power steering.
  • Check Engine Light: When a P0551 code occurs, the Check Engine light may illuminate on your instrument panel, indicating a problem with the power steering system.
  • Unusual steering wheel behavior: The steering wheel may react in unexpected ways to the driver's input, such as hesitation or jerking when turning.

These symptoms can occur in varying degrees and depend on the specific problem in the power steering system. If you notice any of these symptoms, it is recommended that you contact a qualified auto mechanic to diagnose and repair the problem.

How to diagnose a fault code P0551?

The following steps are recommended to diagnose DTC P0551:

  1. Checking the oil level in the power steering system: Make sure the power steering oil level is within the recommended range. Insufficient oil may be one of the causes of the P0551 code.
  2. Checking wiring and connectors: Inspect the wires and connectors connecting the power steering pressure sensor to the electronic engine control module (PCM). Make sure the wires are intact and undamaged and the connectors are well connected.
  3. Pressure sensor diagnostics: Using a multimeter, check the operation of the power steering pressure sensor. Compare the sensor readings to the manufacturer's recommended specifications.
  4. Checking the power steering: Check the operation of the power steering unit itself for problems. This may include inspection for oil leaks, unusual sounds, or other abnormalities.
  5. Scanning error codes: Connect the vehicle to a diagnostic scan tool to read error codes and view pressure sensor data. This will help identify any additional problems that may be related to the P0551 code.
  6. PCM testing: If all other checks fail to identify the cause of the P0551 code, testing or replacing the PCM may be necessary as malfunctioning of this device may also cause this error.

If, after carrying out the above steps, the cause of the P0551 code remains unclear, it is recommended that you contact a qualified auto mechanic or auto repair shop for further diagnosis and repair.

Diagnostic errors

When diagnosing DTC P0551, the following errors may occur:

  • Misinterpretation of data: The error may be an incorrect interpretation of the data received from the power steering pressure sensor or PCM. This may lead to incorrect conclusions about the cause of the malfunction.
  • Insufficient verification: Failure to sufficiently check all possible causes of the P0551 code may result in missing the real problem. For example, not checking the power steering oil level may result in missing a low oil level problem.
  • Faulty sensors or components: If the problem is not found when checking the pressure sensor or other components, but the problem persists, it may be due to a problem with the sensor itself, the wiring, or other components of the power steering system.
  • Incorrect interpretation of error code: Some auto mechanics may misinterpret the P0551 code or draw incorrect conclusions about the cause of the problem, which can lead to erroneous repair actions.
  • Lack of professional equipment: Some problems related to pressure sensors or PCM can be difficult to diagnose without special equipment such as a diagnostic scanner. The lack of such equipment can make it difficult to accurately diagnose the problem.

It is important to carry out a thorough and systematic diagnosis, taking into account all possible causes of the P0551 code, in order to avoid mistakes and ensure the correct solution to the problem.

How serious is the fault code? P0551?

Trouble code P0551 indicates a problem with the power steering pressure sensor. Although this may cause some inconvenience and restriction in driving, in most cases it is not a critical problem that directly threatens driver safety or vehicle performance.

However, a malfunction in the power steering system can affect the vehicle's handling, especially at low speeds or when maneuvering in parking lots. This can create danger in case of unexpected situations on the road.

Therefore, although the P0551 code is most likely not an emergency, it should be carefully considered and resolved as soon as possible to avoid possible vehicle drivability problems in the future.

What repair will help eliminate the code? P0551?

Troubleshooting trouble code P0551 may include the following steps:

  1. Replacing the pressure sensor in the power steering system: If the pressure sensor is truly faulty or has failed, it must be replaced with a new one that complies with the manufacturer's recommendations.
  2. Checking and replacing wiring and connectors: If damaged wires or connectors are found, they must be replaced or repaired.
  3. Diagnostics and repair of power steering: In some cases, the problem may not be with the pressure sensor, but with the power steering device itself. In this case, it may require diagnostics and repair.
  4. Checking and updating PCM software: In rare cases, the P0551 code may be caused by the PCM software not operating properly. In this case, a software update or reprogramming of the PCM may be required.
  5. Additional checks: After performing basic repairs, additional checks and tests should be performed to ensure that the problem is completely resolved and the code does not return.

It is important to have a qualified auto mechanic or auto repair shop perform diagnostics and repairs because pinpointing the cause and properly correcting the problem may require specialized equipment and experience.

What is P0551 Engine Code [Quick Guide]

P0551 – Brand-specific information


Trouble code P0551 relates to the power steering system and can be found in various makes of cars, some of them with their meanings:

These are just some of the possible makes of cars where the P0551 code may occur, and its meaning may vary slightly depending on the specific model and year of the vehicle.

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