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

P0041

O2 Sensor Signals Swapped Bank 1 Sensor 2/Bank 2 Sensor 2

The post-cat oxygen sensors of bank 1 and bank 2 appear to be wired the wrong way around — bank 1 reacts when bank 2 should and vice versa. Typically after recent service.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number– / 41

Possible causes

  • Sensors swapped after replacement high

Symptoms

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

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 10–100 €
  • Estimated time: 0.3–1 h
  • Component: oxygen sensor b1s2
  • Component: oxygen sensor b2s2
  • 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