OBD-II code · Powertrain (generic, extended)
P2D1D Reductant System Leak Detected – Small Leak
The SCR module detects a small leak in the reductant system based on pressure decay rate after dosing pause. Slow loss of DEF/AdBlue.
Is it safe to drive with P2D1D?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyFitting or connection loose
- PossibleSeal aged at injector or pump
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)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–6 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Reductant Lines, Reductant Injector, Reductant Pump, Scr Module
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.