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

P2394

Diesel Intake Air Flow B Control Stuck Open

Diesel intake air flow valve B is mechanically stuck open - the ECU cannot close it for anti-shudder shutdown or EGR mixing assistance.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number3 / 94

Possible causes

  • Valve stuck open due to soot or broken linkage high
  • Carbon or debris buildup preventing free movement low
  • Component wear with age - mechanical play low

Inspection / repair

  • Difficulty: medium
  • DIY: possible
  • Estimated cost: 200–1000 €
  • Estimated time: 1–4 h
  • Component: diesel intake air flow b
  • MIL / check engine light
  • emissions-relevant

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