OBD-II code · Powertrain (generic, extended)
P225B NOx Sensor Calibration Memory (Bank 1 Sensor 2)
The factory calibration memory of the NOx sensor on bank 1 sensor 2 cannot be read or contains a checksum error. Each NOx sensor ships with a unique calibration table programmed at the factory.
Is it safe to drive with P225B?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelySensor calibration memory corrupt
- Less likelyModule software outdated, reflash may resolve
- Less likelySupply voltage outside specification
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
- 1–3 h
- Emissions test
- Likely to fail
- Parts involved
- Nox Sensor
Related codes
- P225ANOx Sensor Calibration Memory (Bank 1 Sensor 1)
- P2258Secondary Air Injection System Control A Circuit High
- P2259Secondary Air Injection System Control B Circuit Low
- P225CNOx Sensor Performance - Signal Biased/Stuck High (Bank 1 Sensor 1)
- P225DNOx Sensor Performance - Signal Biased/Stuck Low (Bank 1 Sensor 1)
- P225ENOx Sensor Performance - Signal Biased/Stuck High (Bank 1 Sensor 2)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.