P055A code meaning
Engine Oil Pressure Sensor/Switch B Circuit
Powertrain system Generic code P05xx codes Check engine light
What P055A means
Oil pressure sensor B is a second sensor, usually in the oil feed to the cam phasers or valve lift switching – on GM's 2.5 L (2014 Impala and Malibu) in the camshaft cover – while sensor A measures the main gallery. Documented only by GM (type B, two trips); Ford uses no sensor B. P055A is the general circuit fault without low/high assignment. No manufacturer document available to us uses it – GM reports sensor B only as P055B–P055D. The module then uses a substitute value and may set cam phasers or valve lift to their base position.
P055A at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P055A
- Check engine light on
- Cam phasing or valve lift switching possibly restricted
- Often no noticeable symptoms
Common causes of P055A
- Most likelyConnector or harness to sensor B open, corroded or oily
- PossibleSensor B open internally
- PossibleShared 5 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
Oil pressure sensor bSensor wiringEngine control module
What each part of P055A 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. |
| 5A | The exact fault in that area. |
What to do next
- Note P055A 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 P055A
What does P055A mean?
P055A means "Engine Oil Pressure Sensor/Switch B Circuit". Oil pressure sensor B is a second sensor, usually in the oil feed to the cam phasers or valve lift switching – on GM's 2.5 L (2014 Impala and Malibu) in the camshaft cover – while sensor A measures the main gallery. It is a generic code, so it means the same on every make.
Is it safe to drive with P055A?
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 P055A fail an emissions test?
Yes, it can. P055A 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 P055A to fix?
Difficulty: medium. A typical repair takes 0.5 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P055A clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.