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 or reserved

P3478

Cylinder Deactivation Oil Pressure Switch Bank 2 Performance

The engine control module has detected a rationality fault between commanded oil pressure and the bank 2 cylinder deactivation oil pressure switch state. The switch fails to change state at the expected pressure threshold during deactivation transitions on bank 2.

SystemPowertrain
Typegeneric or reserved
GroupP3
Range / number4 / 78

Possible causes

  • Pressure switch sticky or contaminated high
  • Oil control valve slow to respond medium
  • Low system oil pressure low

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 120–1000 €
  • Estimated time: 1–5 h
  • Component: oil pressure switch
  • Component: oil control valve
  • 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