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Summary
  • Diagnostic trouble code (DTC) P0551 indicates “Power Steering Pressure Sensor Circuit Range / Performance.”
  • The powertrain control module (PCM) will report this code if it can’t detect the correct electrical change from the power steering pressure sensor when angle change is present at slow speeds.
  • Common causes of the P0551 code are a defective power steering pressure sensor, a power steering fluid leak, and a broken or damaged wiring harness.
  • A vehicle that sets a P0551 code can show symptoms like erratic idling, poor handling, and the engine stalling.

The power steering pressure sensor ensures that there is enough pressure to allow you to turn the steering wheel easily. If necessary, it can open the circuit to the air conditioning compressor clutch whenever the driver turns the steering wheel, which reduces engine load while powering the steering pump. It also alerts the powertrain control module (PCM) that engine idle speed should be maintained.

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If the PCM is unable to detect the appropriate electrical change from the power steering pressure sensor, on-board diagnostics (OBD) may log engine code P0551.

What Does the P0551 Code Mean?

Diagnostic trouble code (DTC) P0551 stands for “Power Steering Pressure Sensor Circuit Range/Performance.”

The power steering pressure sensor signals the PCM that engine idle speed should be held at a specific level whenever the power steering system is operated at low speeds.

Power Steering Pressure Switch Isolated Background
A defective power steering pressure switch may prevent the PCM from increasing the engine idle speed when turning.

If the PCM is unable to detect the appropriate electrical change from the power steering pressure sensor when angle change is present at slow speeds, the PCM will set a P0551 trouble code.

A defective power steering pressure switch may also prevent the PCM from increasing the engine idle speed when turning.

Note: The definition of code P0551 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Possible Causes of the P0551 Code?

  • Defective power steering pressure sensor
  • Leaking power steering fluid
  • Broken or damaged wiring harness
  • Defective fuse or relay
  • Issues with the pin or connector (corroded, melted, broken lock tab, etc.)

What are the Common Symptoms of the P0551 Code?

  • Erratic idling
  • Poor handling
  • Engine stalling
  • Whining noises
  • Poor steering performance (choppy turning)
See also  P0550 Code: Power Steering Pressure Sensor/Switch Circuit

How to Diagnose the P0551 Code

Engine code P0551 is a generic trouble code that can be logged in OBD-equipped vehicles. Note, however, that protocols for diagnosing this code and the necessary steps for repair may vary depending on your vehicle’s year, make, and model.

If you’re not comfortable with conducting a diagnostic test on your vehicle, it might be best to have a licensed mechanic do the job instead. Here are a couple of videos to give you some ideas on what the process might involve:

How to Fix the P0551 Code

Attempting to fix code P0551 may be confusing without the right tools and know-how. In this case, it might be better to bring your vehicle to a licensed mechanic to ensure that the necessary steps involved in fixing the issues are followed correctly. If you think you can fix the problem by yourself, make sure to brush up on the proper diagnostic and repair procedures before proceeding. Repair manuals or an online repair database are useful tools that have vehicle-specific repair information.

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Where to Get Car Fluids and Replacement Parts to Clear Code P0551

Depending on the issue that triggered the P0551 code, you might have to refill your ride’s power steering fluid or replace a part to resolve it. Thankfully, CarParts.com has what you need on hand and ready to ship from a warehouse near you.

Shopping only takes a few minutes, thanks to our vehicle selector and search filters. If you have any questions, our round-the-clock customer service team is always just a call away via our toll-free hotline.

We source our car fluids and parts from trusted manufacturers in the industry to guarantee you get your money’s worth. They also come with a low-price and lifetime replacement guarantee to maximize your hard-earned cash.

Shop now to resolve this trouble code in no time!

About The Author
Written By Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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