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).
Medium severity. Can I keep driving?Avoid long trips and hard acceleration. If you smell fuel or the car stalls, do not continue.
Symptoms
- Check engine light on
- Hard starting or hesitation when accelerating
- Stumbling under load
- Often no symptoms
Most likely causes
- Sensor drifting or stuck (diaphragm, electronics)
- Genuine low-pressure fault: weak pump, clogged filter, faulty regulator
- Contact resistance at connector or ground
- Fuel pump control module or its control
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P018B means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 1: Air and fuel
- 8B: Specific fault in that system
Frequently asked questions
Can I keep driving with code P018B?
Avoid long trips and hard acceleration. If you smell fuel or the car stalls, do not continue.
What causes code P018B?
The most common causes are: sensor drifting or stuck (diaphragm, electronics); genuine low-pressure fault: weak pump, clogged filter, faulty regulator; contact resistance at connector or ground.
Related codes
- P018AFuel Pressure Sensor B Circuit
- P018CFuel Pressure Sensor B Circuit Low
- P018DFuel Pressure Sensor B Circuit High
- P018EFuel Pressure Sensor B Circuit Intermittent/Erratic
- P008ALow Pressure Fuel System Pressure - Too Low
- P2635Fuel Pump A Low Flow/Performance
Sources
- law.cornell.edu: 13 CCR 1968.2
- gsi.ext.gm.com: 18OBDG04 Engine Diagnostics
- gsi.ext.gm.com: 18OBDG03A Engine Diagnostics
- fordservicecontent.com: OBD Operations Summary Gasoline 2020 2023
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.