P0551 - Power Steering Pressure Sensor Circuit Range/Performance Problem

Introduction

The DTC P0551 error code indicates a problem with the power steering pressure sensor circuit. This code is common in many modern vehicles and can negatively affect the handling and safety of the vehicle. Understanding the symptoms, causes, diagnosis and repair methods of this error code is essential for every auto mechanic.

Symptoms

Symptoms of a P0551 code can vary depending on the vehicle, but some of the most common include:

  • Difficulty in steering, especially at low speeds
  • Warning light on in the instrument cluster
  • Changes in steering wheel sensitivity
  • Abnormal noises coming from the power steering system
  • Possible overheating of the power steering pump

Cause

The causes of a DTC P0551 can be many and include:

  • Power steering pressure sensor fault :
    The sensor may be faulty or damaged, sending incorrect signals to the engine control unit (ECU).

  • Compromised electrical circuit :
    Damaged wires, corrupted connectors, or breaks in the circuit can affect the proper functioning of the sensor.

  • Mechanical problems in the power steering system :
    A faulty power steering pump or a leak in the hydraulic system can cause the sensor to malfunction.

  • Power problems :
    If the supply voltage to the sensor is incorrect, the signal sent to the ECU may be incorrect.

Diagnosis

Diagnosing a P0551 code requires a methodical approach. Here are some steps to follow:

  1. DTC Code Scan :
    Use an OBD-II scan tool to confirm the presence of the P0551 code and identify any related codes such as P0550 (Power Steering Pressure Sensor Circuit - Low) or P0552 (Power Steering Pressure Sensor Circuit - Low).

  2. Visual inspection :
    Check the power steering pressure sensor wiring and connectors for signs of wear, corrosion, or damage.

  3. Sensor Test :
    Use a multimeter to measure the voltage and resistance of the sensor, comparing the results to the manufacturer's specifications.

  4. Checking the power steering pump :
    Check the operation of the power steering pump to ensure there are no leaks or mechanical malfunctions.

  5. Hydraulic pressure control :
    Use a pressure gauge to measure the power steering fluid pressure, making sure it is within normal range.

Resolution and repair

Once the cause of the P0551 code has been identified, the following solutions can be implemented:

  • Replacing the power steering pressure sensor :
    If the sensor is defective, replacement is necessary. Make sure to use a quality replacement.

  • Wiring Repair :
    If there is damage to the wiring or connectors, repair or replace the affected parts.

  • Replacing the power steering pump :
    If the pump is defective, it is essential to replace it to ensure proper functioning of the system.

  • Checking and restoring hydraulic pressure :
    If the pressure is incorrect, check the fluid level and replace if necessary.

Insight: Components involved in code P0551

The P0551 code involves several mechanical and electrical components. Here is a closer look at the main ones:

  • Power steering pressure sensor :
    This sensor measures the fluid pressure in the power steering system and sends this information to the ECU. A malfunction of the sensor can falsely indicate a problem in the system.

  • Power steering pump :
    The pump generates the pressure needed for the power steering system to function. A mechanical failure in this component can affect the pressure and, consequently, the function of the sensor.

  • Engine Control Unit (ECU) :
    The ECU processes the data received from the power steering pressure sensor and regulates the operation of the system. A malfunction of the ECU can lead to incorrect readings and the warning light coming on.

  • Electrical circuit :
    It includes all wiring and connectors that connect the sensor and pump to the ECU. Any open or short circuit in this circuit may cause malfunction.

Conclusions

The DTC P0551 error code is an indicator of problems in the power steering system, which can significantly affect the handling and safety of the vehicle. Through proper diagnosis and targeted resolution, auto repairers can effectively address this problem. Remembering to pay attention to the components involved and following the test procedures can help ensure that the vehicle is running at its best again. Proper maintenance and preventative diagnosis can help avoid future problems in the power steering system and keep the vehicle in ideal condition.

Important
Not all OBD2 codes used by one manufacturer are used by other brands, and may not have the same meaning.
The information presented here is for informational purposes only. We are not responsible for any actions you take on your vehicle. If you have any concerns about repairing your vehicle, please contact your repair shop.