P0551
Power Steering Pressure Sensor/Switch Circuit Range/Performance
Idle control (power steering pressure)
Generic OBD-II
Medium
What it means
P0551 means the power-steering pressure (PSP) sensor is reporting a value outside the expected range. The ECM uses this signal to bump up idle when steering load is high, so the usual effect is an idle dip or surge during low-speed turns rather than any loss of steering. It points to the sensor, its wiring, or fluid pressure — not the steering rack itself.
Medium
Can I keep driving? Usually fine to drive — steering still works, but the engine may dip or surge at idle when you turn at low speed until it's fixed.
Common symptoms
What you'll notice
- Check-engine light on
- Idle dips, surges, or stalls when turning at low speed (e.g. parking)
- Engine doesn't raise idle to compensate for steering load
- No symptoms in some vehicles beyond the stored code
Common causes
Most likely first
- Wiring or connector fault in the power-steering pressure (PSP) sensor circuitLikely
- Failed or out-of-range PSP sensorCommon
- Low power-steering fluid or weak pump pressure skewing the signalCommon
- ECM fault (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and inspect the PSP sensor connector for damage, corrosion, or looseness.
- Check power-steering fluid level and condition; low or aerated fluid can drive the signal out of range.
- Back-probe the sensor signal and compare against a spec while turning the wheel; replace the PSP sensor if out of range.
- Repair any damaged wiring, then clear and re-test. Suspect the ECM only after wiring and sensor check out.
FAQ
Quick answers
Is it safe to drive with P0551?+
Generally yes — your steering assist still works. The main effect is the ECM not adjusting idle for steering load, so it may stumble when you turn while parking.
Can I just clear P0551?+
You can, but it returns until the circuit or sensor fault is fixed. Clear it after the repair to confirm the fix held.
Related codes
Often seen with P0551
Read & clear P0551 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX