P055CEngine Oil Pressure Sensor/Switch B Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- 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. P055C means the signal is too low – an open 5 V supply or signal line or a short to ground, not low oil pressure. GM sets it at a reading of 10 or less in 120 of 150 samples; real low pressure is P0524. The module uses a substitute value.
- What you may notice
- Check engine light on
- Cam phasing or valve lift switching possibly restricted
- Often no noticeable symptoms
- Likely causes
- Likely5 V supply or signal open, connector loose or corroded
- PossibleSignal shorted to ground (chafing)
- PossibleSensor B faulty internally
- RareModule's 5 V reference disturbed
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €40 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.