OBD-II code · Powertrain (generic, extended)
P205B Reductant Tank Temperature Sensor A Circuit Range/Performance
DEF tank temperature sensor A reads within electrical range but plausibility fails — sensor sticks during a heating cycle.
Is it safe to drive with P205B?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySensor drifts
- Less likelySensor element aged beyond calibration window
- Less likelySensor mounting loose - signal damping
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
- 0.7–2.5 h
- Emissions test
- Likely to fail
- Parts involved
- Reductant Tank Temperature Sensor
Related codes
- P205AReductant Tank Temperature Sensor A Circuit
- P2058Reductant Injection Valve Circuit High (Bank 2 Unit 2)
- P2059Reductant Injection Air Pump Control Circuit/Open
- P205CReductant Tank Temperature Sensor A Circuit Low
- P205DReductant Tank Temperature Sensor A Circuit High
- P205EReductant Tank Temperature Sensor A Circuit Intermittent/Erratic
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.