P2E56Exhaust Pressure Sensor C Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2E56 means the signal of exhaust pressure sensor C stays under the lowest voltage a working sensor can produce. Analogue exhaust pressure sensors return a share of their 5 V reference; Ford's petrol transfer function for sensor A puts 49 kPa at 0.3 V and flags anything under 0.21 V for 5 s, while its 2023 diesels use 0.1 V for 2 s. No manufacturer publicly documents P2E56. A signal wire shorted to ground, a lost 5 V reference or a sensor with a failed output stage are the usual reasons; if several sensors on the same reference set low codes at once, the reference or the module is the better suspect. Functions that use the value, such as EGR or turbocharger control, then rely on substitute values, so power may be limited. The high-side code is P2E57, sensor A's low code P0472.
- What you may notice
- MIL on
- Possible loss of power from substitute values
- Further low codes of sensors sharing the reference
- Likely causes
- LikelySignal wire of sensor C shorted to ground
- Possible5 V reference open or pulled down by another sensor
- PossibleSensor C output stage failed
- 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 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.