Powertrain, generic · Fuel and air metering

P018B Fuel Pressure Sensor B Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

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).

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

Symptoms

  • Check engine light on
  • Hard starting or hesitation when accelerating
  • Stumbling under load
  • Often no symptoms

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–400
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

fuel pressure sensor bsensor wiringsensor reference voltagefuel pump

Related codes

P018AP018CP018DP018EP008AP2635

References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com, fordservicecontent.com.