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

P2AD8

Reductant Pump Motor Position Sensor Circuit Low

Voltage on the reductant pump motor position sensor signal line is below the expected window. Wire shorted to ground or sensor short.

SystemPowertrain
Typegeneric / SAE
GroupP2
Range / numberA / D8

Possible causes

  • Signal wire shorted to ground high
  • Internal sensor short medium
  • Connector pins corroded - high contact resistance 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: medium
  • DIY: shop recommended
  • Estimated cost: 200–1000 €
  • Estimated time: 1–4 h
  • Component: reductant pump motor position sensor
  • Component: wiring harness
  • Component: scr module
  • MIL / check engine light
  • emissions-relevant
  • 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