P0550 low

Power Steering Pressure Sensor/Switch Circuit

The P0550 code means the vehicle's onboard diagnostic system has detected: Power Steering Pressure Sensor/Switch Circuit. This is a low severity code.

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Keep driving?: Yes, but fix soon
DIY difficulty: moderate
Estimated cost: $60 - $250 (parts and labor)

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Common Symptoms

Engine idle drops when steering wheel is turned
Engine stalls when parking or turning at low speed
Hard steering at idle
Idle speed does not increase during steering maneuvers
Check engine light on

Probable Causes (Ranked by Likelihood)

Faulty power steering pressure (PSP) sensor/switch Very High
Damaged or corroded PSP sensor wiring or connector High
Low power steering fluid level Moderate
Power steering pump failure causing abnormal pressure Moderate
PCM input circuit failure Low

Step-by-Step Diagnostic Procedure

Check power steering fluid level and condition -- top off if low
Monitor PSP sensor signal with a scan tool while turning the steering wheel lock to lock
Inspect PSP sensor connector for corrosion, fluid contamination, or loose pins
Measure PSP sensor voltage -- should change when steering wheel is turned (typically 0.5V to 4.5V range)
Check for 5V reference voltage and good ground at the sensor connector

Frequently Asked Questions

Can I drive with code P0550?

Yes, you can drive safely. The main issue is that the engine may stall when you turn the steering wheel at low speeds or during parking. The PCM uses the PSP signal to raise idle speed during steering loads, so without it, the engine may lug down.

What does the power steering pressure sensor do?

The PSP sensor tells the PCM when the power steering system is under load (when you turn the wheel). The PCM then increases idle speed to compensate for the extra load on the engine from the power steering pump, preventing stalling.

Do electric power steering vehicles have this sensor?

No. Vehicles with electric power steering (EPS) do not have a hydraulic power steering pump or PSP sensor. This code applies only to vehicles with traditional hydraulic power steering systems. Most newer vehicles (2012+) use electric power steering.