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

P01F1

O2 Sensor Circuit Bank 1 Sensor 4

Generic electrical fault on the bank 1, sensor 4 oxygen sensor (fourth sensor downstream — used on systems with multiple cat stages or NOx-trap diagnosis).

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / F1

Possible causes

  • Sensor failed high

Symptoms

  • Check engine light on
  • Increased fuel consumption
  • Possible rough idle or hesitation
  • Failed emissions test

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 80–400 €
  • Estimated time: 0.5–2 h
  • Component: oxygen sensor b1s4
  • Component: sensor wiring
  • MIL / check engine light
  • emissions-relevant
  • drive cycle required

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