OBD-II Code P0550 — What It Means & How to Fix It

What Does This Error Mean?

P0550 means the power steering pressure sensor circuit is not working properly. This sensor tells the engine computer when you are turning the steering wheel hard. The computer uses that information to increase idle speed slightly, preventing stalling when the power steering pump loads the engine. A faulty sensor can cause the engine to stall at low speeds during turns. This should be repaired to prevent stalling and potential loss of control.

Affected Models

All vehicles 1996+ with hydraulic power steering
Common in Honda Civic and Accord
Common in Ford vehicles
Common in GM cars and trucks
Common in Toyota and Lexus vehicles

Common Causes

Faulty power steering pressure sensor sending incorrect voltage signal
Damaged or corroded wiring between the sensor and the engine computer
Loose or corroded connector at the power steering pressure sensor
Low power steering fluid level affecting hydraulic pressure readings
Failed power steering pump producing abnormal pressure

How to Fix It

Check the power steering fluid level. The reservoir is usually a small container near the power steering pump under the hood. Top off with the correct fluid if low.

Low fluid can cause abnormal pressure that triggers this code. Always check fluid first.
Locate the power steering pressure sensor. It is typically threaded into the power steering pressure line or pump housing. Inspect the connector for corrosion or damage.

On most vehicles, the sensor is near the power steering pump on the engine. Refer to your repair manual for exact location.
Inspect the wiring harness from the sensor back toward the engine computer. Look for damaged insulation, especially near hot engine components or areas where the harness may rub.

The wiring near the power steering pump is exposed to heat and movement, which causes wear over time.
Test the sensor with a multimeter. With the key on and engine off, check that the reference voltage (typically 5V) is present at the sensor connector. Then check the signal output.

If reference voltage is absent, suspect a blown fuse or open wiring to the sensor.
Replace the power steering pressure sensor if electrical testing points to it as the fault. Clear the code, start the engine, and test drive including making full turns at low speed.

After the repair, verify the engine does not stumble or stall when turning the steering wheel to full lock.

When to Call a Professional

Power steering pressure sensor replacement is a straightforward DIY job for most vehicles. Sensors typically cost $20 to $80 for the part. Labor at a shop is $50 to $100 since the sensor is usually accessible. If the power steering pump itself has failed, pump replacement is $150 to $400 for parts plus labor. Total pump replacement at a shop typically runs $300 to $600.

Frequently Asked Questions

Can P0550 cause my car to stall?

Yes, this is one of the most common symptoms. When the computer does not receive the steering pressure signal, it cannot increase idle speed during hard turns. The extra load from the power steering pump can drag down the idle and stall the engine. This is especially noticeable in parking lots at very low speeds.

Does this code mean my power steering is failing?

Not necessarily. P0550 specifically relates to the sensor circuit, not the steering itself. Your steering may work perfectly fine while this code is set. However, always check fluid level and steering feel to rule out a pump problem.

My car has electric power steering — can it still get P0550?

P0550 is specific to hydraulic power steering systems with a pressure sensor. Electric power steering (EPS) uses a different system and different codes. If your car has EPS and shows P0550, double-check the code with a scan tool — it may be a different, vehicle-specific code.