P018CFuel Pressure Sensor B Circuit 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
- Fuel pressure sensor B is a second fuel pressure sensor; which one is up to the manufacturer. On GM it is the low-pressure sensor in the supply line of direct-injection engines (0–743 kPa), read by the engine module or the fuel pump control module; on Ford engines with dual injection it is the sensor on the port-injection rail (0.5–4.5 V for about 0–70 psi). Sensor A is the high-pressure rail sensor (P0190–P0194). P018C means the signal voltage is below its lower limit – a signal wire shorted to ground, or an open signal or 5 V reference wire; a short on another sensor sharing the reference can also pull it down. GM sets it below 4 % of the reference (about 0.2 V), or below 0.14 V when the sensor is read by the fuel pump module, in 64 or 72 of 80 samples; two trips. Ford sets it below 0.049 V for 8 s. The control module then uses a fixed value or fixed pump control.
- What you may notice
- Check engine light on
- Starting problems
- Lack of power or stumbling
- Sometimes no symptoms
- Likely causes
- LikelySignal wire shorted to ground or open
- Possible5 V reference missing or shorted (also by another sensor on the circuit)
- PossibleSensor faulty
- PossibleConnector corroded
- 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: €50 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.