P0550 code meaning
Power Steering Pressure Sensor/Switch Circuit
Powertrain system Generic code P05xx codes Check engine light
What P0550 means
Hydraulic power steering has a pressure switch or sensor on the high-pressure line; when the wheel is turned at standstill, pump pressure and engine load rise sharply, so the engine module raises idle air in advance to stop the engine stalling. That makes it an input to idle control under CARB. Switches (Saab, Mitsubishi) ground a pull-up; analogue 5 V sensors (Toyota) give about 0.45 V at zero pressure. GM's and Ford's tables do not use P0550–P0554. P0550 is the general circuit fault. No manufacturer document available to us uses it. Without the signal the engine can drop or stall at full lock, or the module raises idle permanently as a substitute.
P0550 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0550
- Check engine light (depending on the maker)
- Idle drops when steering at standstill, engine may stall
- Raised idle (substitute value)
Common causes of P0550
- Most likelyConnector or wire open or corroded (splash zone at the pump)
- Most likelySensor or switch faulty, often also leaking
- Possible5 V reference or ground disturbed
- Less likelyEngine module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Power steering pressure switchSensor wiringEngine control module
What each part of P0550 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| 50 | The exact fault in that area. |
What to do next
- Note P0550 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0550
What does P0550 mean?
P0550 means "Power Steering Pressure Sensor/Switch Circuit". Hydraulic power steering has a pressure switch or sensor on the high-pressure line; when the wheel is turned at standstill, pump pressure and engine load rise sharply, so the engine module raises idle air in advance to stop the engine stalling. It is a generic code, so it means the same on every make.
Is it safe to drive with P0550?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0550 fail an emissions test?
Yes, it can. P0550 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0550 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0550 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.