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

P202E

Reductant Injection Valve Circuit Range/Performance (Bank 1 Unit 1)

The DEF (urea) injection valve on bank 2, unit 1 does not respond to commands within the expected range — flow or response time off-spec, no obvious electrical fault.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number– / 2E

Possible causes

  • DEF crystallisation in nozzle high
  • Sensor element aged beyond calibration window low
  • Sensor mounting loose - signal damping low

Symptoms

  • Check engine light or NOx warning on
  • AdBlue/DEF level or quality warning
  • Possible no-start countdown after ignore period
  • Failed emissions inspection (NOx)

Inspection / repair

  • Difficulty: hard
  • DIY: shop recommended
  • Estimated cost: 150–1200 €
  • Estimated time: 1–4 h
  • Component: reductant injection valve
  • Component: reductant metering unit
  • 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