Powertrain
generic / SAE
P23C1
NOx Sensor Sensing Element Bank 1 Sensor 3
The downstream NOx sensor on bank 1 reports that its internal ZrO2 sensing element is no longer producing valid pumping currents - the element has lost its electrochemical response, typically because the active ceramic layer has been poisoned, cracked, or burnt out.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number3 / C1
Possible causes
- Sensor element poisoned by silicone or sulphur high
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)
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 400–850 €
- Estimated time: 1–1.8 h
- Component: nox sensor b1s3
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012