Fuel and air

P018B — Fuel Pressure Sensor "B" Circuit Range/Performance

Severity: medium Drive with care, to a shop

What P018B means

The engine control unit constantly compares the signal from fuel pressure sensor "B" with the expected pressure in the rail or fuel line and with fuel pump operation. With P018B, the signal does not change as expected or falls outside the allowed range. The cause may be the sensor, its wiring, or an actual fuel pressure problem.

Symptoms

  • Check Engine light on
  • Hard starting or long cranking
  • Hesitation and poor acceleration
  • Reduced power or limp mode
  • Higher fuel consumption
  • Rough idle or stalling

Possible causes

  1. Faulty fuel pressure sensor "B"
  2. Damaged or corroded wiring or connector (open, short to ground or power)
  3. Actual incorrect fuel pressure: weak pump or clogged filter
  4. Faulty pressure regulator or control valve
  5. Leaking injectors or excessive return flow
  6. Faulty PCM (rare)

How to diagnose

  1. Scan for codes and freeze frame data, and note any other fuel system codes
  2. Compare specified and actual rail pressure at cranking, idle and under load
  3. Test low-pressure supply (pressure and volume) and check the fuel filter
  4. Inspect the sensor harness and connector for corrosion, chafing and poor contact
  5. Use a multimeter to check sensor power, ground and reference voltage
  6. Test the pressure regulator or control valve operation
  7. Where applicable, measure injector return flow
  8. Compare the sensor reading against a mechanical test gauge

Common fixes

  • Replace fuel pressure sensor "B"
  • Repair damaged wiring and connectors
  • Replace the fuel filter or fuel pump if pressure is out of spec
  • Replace the regulator or control valve
  • Reflash or replace the PCM only after everything else is ruled out

Questions and answers

What does P018B mean?

The signal from fuel pressure sensor "B" is outside the expected range or does not behave as expected while the pump runs. You need to determine whether the sensor, wiring or actual pressure is at fault.

Can I drive with P018B?

Only a short distance to a shop. The engine can lose power or stall, so do not put off the repair.

Should I replace the sensor right away?

No. First compare its reading with a mechanical gauge and check the wiring and fuel supply, otherwise a new sensor may not fix the problem.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.