P0550
Power Steering Pressure Sensor/Switch Circuit
Idle control (power steering)
Generic OBD-II
Medium
What it means
P0550 means the ECM has seen an out-of-range or interrupted signal from the power steering pressure sensor. That sensor tells the engine when steering effort is loading the pump so it can nudge idle up. Steering keeps working, but with a bad signal the idle may dip or stall briefly during slow, tight turns.
Medium
Can I keep driving? Usually fine to drive — the car steers normally, but the ECM may not raise idle when you turn, so idle can dip or briefly stall during slow, tight maneuvers.
Common symptoms
What you'll notice
- Check-engine light on
- Idle dips or briefly stalls when turning at low speed (e.g. parking)
- Slight idle roughness under steering load
Common causes
Most likely first
- Faulty power steering pressure (PSP) sensor/switchLikely
- Damaged, chafed, or corroded wiring at the PSP sensor connectorCommon
- Loose or poorly seated electrical connectorCommon
- ECM fault (rare — check wiring first)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the code, then locate the PSP sensor (screwed into a high-pressure power steering line).
- Inspect the sensor connector and wiring for corrosion, damage, or a loose fit; clean and reseat.
- Back-probe the signal and reference wires and compare readings against the ECM to isolate a sensor vs. wiring fault.
- Replace the PSP sensor if its signal is out of range with good wiring.
- Clear the code and re-test; only suspect the ECM if the circuit checks out.
FAQ
Quick answers
Is it safe to drive with P0550?+
Generally yes. Steering itself is unaffected; the main risk is a slight idle dip or brief stall during slow, tight turns because the ECM isn't compensating for steering load.
Can I just clear P0550?+
It will clear, but it returns once the ECM sees the same faulty signal again. Fix the sensor or wiring to keep it away.
Related codes
Often seen with P0550
Read & clear P0550 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