OBD-II code · Powertrain (generic, extended)
P23B7 NOx Sensor Heater Control Circuit Range or Performance Bank 1 Sensor 3
Same as P23B1 with the heater control loop in plausible range yet not matching the heater model - aged heater or harness resistance.
Is it safe to drive with P23B7?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyHeater element aged
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
- 1–2 h
- Emissions test
- Likely to fail
- Parts involved
- Nox Sensor B1s3 Heater
Related codes
- P23B4NOx Sensor Heater Sense Circuit Bank 1 Sensor 3
- P23B5NOx Sensor Heater Sense Circuit Range or Performance Bank 1 Sensor 3
- P23B6NOx Sensor Supply Voltage Circuit Bank 1 Sensor 3
- P23B8NOx Sensor Heater Sense Circuit Low Bank 1 Sensor 3
- P23B9NOx Sensor Heater Sense Circuit High Bank 1 Sensor 3
- P23BANOx Sensor Heater Sense Circuit Intermittent Bank 1 Sensor 3
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.