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!

Network generic / SAE

U02AF

Lost Communication With Turbocharger Turbine Inlet Valve Position Sensor

The vehicle bus reports loss of communication with the turbocharger turbine inlet valve position sensor. Position feedback for variable inlet geometry on twin-scroll/sequential turbo systems is missing.

SystemNetwork
Typegeneric / SAE
GroupU0
Range / number2 / AF

Possible causes

  • Bus wiring open or shorted high
  • Module without power or ground medium
  • Module failed medium

Symptoms

  • Multiple warning lights may illuminate
  • Affected modules may go into limp mode or shut down
  • Specific functions inoperative depending on module
  • Diagnostic tools may show communication faults

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 200–2000 €
  • Estimated time: 1–4 h
  • Component: turbine inlet valve position sensor
  • Component: vehicle bus wiring
  • 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