Can you keep driving?
Can you keep driving?
Stop driving if any of these apply
- !The system loses function completely or starts making noise or leaks that suggest a real mechanical problem.
- !The warning light is accompanied by a severe drivability or safety issue.
What to check first
Step-by-step checks
- 1
Free - no tools
Check the power steering fluid level and look for leaks before replacing parts
- 2
Free - no tools
Inspect the pressure sensor and connector for oil contamination or damaged pins
- 3
Basic tool needed
Notice whether steering gets heavier at idle and lighter at higher RPM, because that behavior helps separate sensor from pump issues
- 4
Basic tool needed
If live data is available, compare the pressure reading with steering effort changes
- 5
Basic tool needed
If the belt-driven pump is noisy or slipping, do not ignore that side
If the code returns
- -If fluid and pump checks are good, the sensor or wiring becomes more likely.
- -If the code returns after a repair, verify the signal under actual steering load.
- -If steering assist is clearly weak, fix the hydraulic side before chasing the sensor alone.
Background
What this code means
P0551 is a generic OBD-II pressure-sensor or pressure-switch code.
These codes often point to a sensor, wiring, fluid-level, or pressure-supply issue rather than the expensive component itself.
Steering assist may vary more than normal, especially at idle or when parking.
Diagnosis
Common causes
Biased pressure sensor
The sensor can drift and report the wrong range.
Fluid leak or low fluid
A real steering issue can trigger the code.
Connector or wiring issue
A bad connection can distort the reading.
Pump or belt problem
A mechanical pressure issue can confuse the system.
Avoid these mistakes
What not to do
- xDo not replace a pump or compressor first if the sensor, wiring, or fluid level is obviously the issue.
- xDo not keep driving if the system is making noise, leaking fluid, or losing function quickly.
Parts
Parts that may need replacing
See also
Related OBD codes
P0550
P0550 usually means the power steering pressure sensor or switch circuit is not behaving correctly.
P0552
P0552 usually means the power steering pressure signal is reading too low.
P0553
P0553 usually means the power steering pressure signal is reading too high.
P0554
P0554 usually means the power steering pressure signal is intermittent.
Source notes
Generic OBD-II (SAE J1979 / ISO 15031-5). P0551 was expanded around common power-steering pressure signal range/performance faults, including sensor bias, wiring issues, and hydraulic pressure problems.
This guide is written as a generic multi-make reference, so bulletin history, sensor locations, and repair order can still change by manufacturer and engine family.
This is generic OBD-II guidance and should not override vehicle-specific service information. Exact diagnosis and repair steps vary by make, engine family, and model year.
Last reviewed: 2026-04-10
Reference: Open reference