OBD-II code · Powertrain (generic, extended)
P23BA NOx Sensor Heater Sense Circuit Intermittent Bank 1 Sensor 3
Same as P23B4 with intermittent or erratic signal. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with P23BA?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyIntermittent contact at connector
- Less likelyConnector with intermittent contact under vibration
- Less likelyHarness routed against vibrating component
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
- P23B7NOx Sensor Heater Control Circuit Range or Performance Bank 1 Sensor 3
- P23B8NOx Sensor Heater Sense Circuit Low Bank 1 Sensor 3
- P23B9NOx Sensor Heater Sense Circuit High Bank 1 Sensor 3
- P23BBNOx Sensor Heater Resistance Bank 1 Sensor 3
- P23BCNOx Sensor Calibration Memory Bank 1 Sensor 3
- P23BDNOx Sensor Performance Signal Biased or Stuck High Bank 1 Sensor 3
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.