OBD-II code · Powertrain (generic, extended)
P206A Reductant Quality Sensor Circuit
A general electrical fault is reported on the DEF (urea) quality sensor — measures urea concentration via ultrasonic or refractive method to detect water dilution or wrong fluid.
Is it safe to drive with P206A?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelySensor failed
- PossibleHarness fault
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
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–4 h
- Emissions test
- Likely to fail
- Parts involved
- Reductant Quality Sensor, Reductant Tank
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.