P2AD9
Reductant Pump Motor Position Sensor Circuit High
Voltage on the reductant pump motor position sensor signal line is above the expected window. Wire shorted to B+ or sensor open.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
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)
Common causes
Ordered by how often each turns out to be the cause.
- Signal wire shorted to B+Common
- Open sensorPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Reductant Pump Motor Position Sensor
- Wiring Harness
- SCR Module
P2AD9 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.