OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

P027B

Fuel Pump Module B Control Circuit Range/Performance

Fuel pump module B does not respond as expected. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number2 / 7B

Possible causes

  • Module B internal fault high
  • Sensor element aged beyond calibration window low
  • Sensor mounting loose - signal damping low

Symptoms

  • Check engine light on
  • Hard start, no start, or stalling under load
  • Power loss especially at high load or rpm
  • Possible long cranking time

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 200–1500 €
  • Estimated time: 1–5 h
  • Component: fuel pump module b
  • MIL / check engine light
  • emissions-relevant
  • drive cycle required
  • limp mode possible

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication