P018BFuel Pressure Sensor B Circuit Range/Performance
- 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). P018B is the plausibility fault. GM checks actively whether the sensor responds: if the pump duty sits at its limit for 5 s or the pressure error varies too little, the module changes pump output and fails the sensor if pressure moves 30 kPa or less – a 'frozen' sensor; two trips. Ford checks the deviation from target instead: more than 20 psi (about 1.4 bar) for 8 s with a plausible target of 35–60 psi, which can also be a genuine pressure problem. A fault-free P018B is a precondition for GM's pump output check (P2635) and Ford's supply checks (P008A/P008B).
- What you may notice
- Check engine light on
- Hard starting or hesitation when accelerating
- Stumbling under load
- Often no symptoms
- Likely causes
- LikelySensor drifting or stuck (diaphragm, electronics)
- PossibleGenuine low-pressure fault: weak pump, clogged filter, faulty regulator
- PossibleContact resistance at connector or ground
- RareFuel pump control module or its control
- 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: €60 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.