P0551: The power steering pressure signal is outside the range the computer expects.
Power steering pressure sensor range/performance
Severity: Inspect soon
The code sits in the power steering system, which is safety-critical. Assistance can be affected if the pump or steering hardware is behind the code, so have it inspected soon rather than ignored.
P0551 in short
P0551 means the power steering pressure sensor or switch signal is out of range or does not behave as the engine computer expects. The sensor itself or a fault in the power steering system are the listed causes. Have the steering system checked soon, because the code can come from the steering hardware as well as the sensor.
The engine computer watches a pressure sensor or switch on the power steering pump. P0551 is the generic title "Power Steering Pressure Sensor Circuit Range/Performance".
The computer uses this signal to raise idle speed when the steering is loaded, so the engine does not stall at parking speeds. Delaware's generic code list and TroubleCodes.net give the same meaning for this code.
Causes come from TroubleCodes.net's probable-cause line. Specific fixes and test values vary by vehicle, so use the service information for your car.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Wiring or connector fault in the sensor circuit
Common general cause- Why it ranks here
- Circuit codes often come from the wiring the signal travels through, though TroubleCodes.net names only the sensor and the steering system for this one, so this ranks as a general cause.
- What would change this
- Rises if the connector is loose, corroded or the harness is chafed near the pump. Falls if reference voltage, ground and signal test normal.
Cause 2: Power steering pressure sensor or switch
Common general cause- Why it ranks here
- The sensor or switch itself is listed as a probable cause by TroubleCodes.net.
- What would change this
- Rises if wiring tests good and the sensor reading does not change with steering load. Falls if the reading follows the steering normally.
Cause 3: Engine control module
Possible — needs testing- Why it ranks here
- TroubleCodes.net lists the computer last; it is rare compared with the wiring and sensor, so it ranks last until those are cleared.
- What would change this
- Rises only after wiring and sensor are both proven good. Falls if repairing the wiring or sensor clears the code.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Read all stored codes and freeze-frame data, and note whether other power steering or engine codes are stored with P0551.
IfOther power steering or engine codes are stored too
It meansDiagnose those together; the circuit or computer may be the shared cause.
IfP0551 is the only code
It meansCheck the sensor circuit next.
Step 2: Look over the power steering fluid level and condition, and inspect the sensor connector and wiring at the pump for damage, corrosion or leaks.
Warning:The steering pump sits near belts and hot or moving parts, and hydraulic fluid can be hot and slippery. Let a shop do the inspection and any electrical testing.
IfWiring or connector is damaged, loose or corroded
It meansRepair it and retest the circuit.
IfWiring is good and the sensor signal does not follow steering load
It meansThe sensor or switch is the likely fault.
IfWiring and sensor are both good
It meansLook at the computer last.
Symptoms
- Check engine light
- No other change in how the car drives (the page does not list specific symptoms)
How to fix
This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.
Parts and cost context
- Engine control module (ECM / PCM):A control module is the last item to suspect. Labour varies; get a quote.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
We don't have reviewed vehicle-specific evidence for P0551 yet. The causes and tests above apply across vehicles.
Related codes
No curated relationships for P0551 yet.
P0551 questions
Is it safe to drive with P0551?
Steering is a safety system. If the steering feels normal, drive carefully and book an inspection soon. If it gets hard to turn or the engine stalls when you turn, stop and get it towed.
Sources and review
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error