P0550 OBD-II Trouble Code: Power Steering Pressure Sensor Circuit Malfunction

P0550 code definition

This Diagnostic Trouble Code (DTC) indicates a Power Steering Pressure Sensor Circuit Malfunction.

What the P0550 code means

Power steering is a luxury most drivers have come to take for granted. The power steering pressure (PSP) sensor facilitates smooth handling by telling the vehicle’s computer how much force should be needed to turn the steering wheel at a certain angle. This signal works in conjunction with signals sent to the PCM by the steering angle sensor (SAS).

When the signal from the PSP sensor and the signal from the SAS are too far out of sync, the power steering pump doesn’t know how much additional support to provide, and the computer will store P0550.

What causes the P0550 code?

One or more of the following faults may cause this DTC:

• A bad PSP sensor
• Damage or a short or open in the PSP sensor wiring
• Loose or damaged PSP sensor connectors
• Bad or incorrect power steering fluid
• A power steering fluid leak
• A faulty power steering pump
• Rack and pinion failure

What are the symptoms of the P0550 code?

You may experience one or more of the following when this code is stored:

• Power steering fluid leak
• Stalling while driving at low speeds
• Decreased fuel economy
• Only manual steering ability
• No noticeable symptoms (rare)
• A lit Check Engine or Service Engine Soon Light (may take up to three drive cycles to illuminate)

How does a mechanic diagnose the P0550 code?

Your mechanic may perform the following diagnostic procedures:

• Visually inspect the PSP sensor and related wiring and connectors
• Check power steering fluid level and condition
• Test the power steering pump for leaks
• Check the condition of the rack and pinion
• Scanning the vehicle’s computer to verify any codes present and record freeze frame data
• Clear the codes to see if they return upon test driving (in order to diagnose an intermittent condition)

Common mistakes when diagnosing the P0550 code

Due to similar symptoms being common when there is a problem with the idle air control system (such as stalling while turning at low speeds), this system may be blamed in error.

How serious is the P0550 code?

The most serious problem associated with a PSP sensor circuit malfunction is the risk of stalling while driving. This can present a safety hazard, as well as being inconvenient. In addition, most drivers are not experienced with manual steering, making driving the vehicle much more challenging under these conditions.

What repairs can fix the P0550 code?

One or more of these measures may be required:

• PSP sensor replacement
• Repair to corroded wiring, opens or shorts in the circuit, or connectors
• Replacing burned or dirty power steering fluid
• Repairing power steering pump leaks
• Pump or rack replacement

Additional comments for consideration regarding the P0550 code

Modern power steering systems are complex units which provide varying pressure depending upon the signals sent to the PCM by the PSP sensor. The proper function of this system has an effect on multiple other vehicle systems, including emissions, RPM calculations, and fuel economy. In addition, driving a vehicle with an existing power steering problem can be physically strenuous as well as potentially dangerous if the vehicle stalls out in the middle of traffic.

You may be tempted to try a power steering repair at home; however, power steering fluid is under tremendous pressure, as well as being flammable. The safest and most efficient way to have this problem repaired is to have a qualified technician diagnose and fix the issue.

Need help with a P0550 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.