Powertrain, generic · Fuel and air metering

P018C Fuel Pressure Sensor B Circuit Low

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). 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.

Likely causes

Signal wire shorted to ground or open
5 V reference missing or shorted (also by another sensor on the circuit)
Sensor faulty
Connector corroded

Symptoms

  • Check engine light on
  • Starting problems
  • Lack of power or stumbling
  • Sometimes no symptoms

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–300
Time0.5–2 h

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

Parts involved

fuel pressure sensor bsensor wiringsensor reference voltage

Related codes

P018DP018AP018BP018EP0192P0641

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