OBD-II code · Powertrain (generic)
P042B Catalyst Temperature Sensor Circuit Range/Performance (Bank 1 Sensor 2)
Catalyst temperature sensor at bank 1 sensor 2 reads in range but plausibility check fails — slow response or stuck reading.
Is it safe to drive with P042B?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySensor drift
- Less likelySensor element aged beyond calibration window
- Less likelySensor mounting loose - signal damping
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2.5 h
- Emissions test
- Likely to fail
- Parts involved
- Exhaust Temperature Sensor
Related codes
- P0426Catalyst Temperature Sensor Circuit Range/Performance (Bank 1 Sensor 1)
- P0436Catalyst Temperature Sensor Circuit Range/Performance (Bank 2 Sensor 1)
- P043BCatalyst Temperature Sensor Circuit Range/Performance (Bank 2 Sensor 2)
- P0428Catalyst Temperature Sensor Circuit High (Bank 1 Sensor 1)
- P0429Catalyst Heater Control Circuit/Open (Bank 1)
- P042ACatalyst Temperature Sensor Circuit (Bank 1 Sensor 2)
- P042CCatalyst Temperature Sensor Circuit Low (Bank 1 Sensor 2)
- P042DCatalyst Temperature Sensor Circuit High (Bank 1 Sensor 2)
- P042EEGR A Control Stuck Open
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.