OBD-II code · Powertrain (generic)
P0426 Catalyst Temperature Sensor Circuit Range/Performance (Bank 1 Sensor 1)
Catalyst temperature sensor at bank 1 sensor 1 reads in range but plausibility check fails — slow response or stuck reading.
Is it safe to drive with P0426?
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
- Catalytic Converter, Exhaust Temperature Sensor
Related codes
- P042BCatalyst Temperature Sensor Circuit Range/Performance (Bank 1 Sensor 2)
- P0436Catalyst Temperature Sensor Circuit Range/Performance (Bank 2 Sensor 1)
- P043BCatalyst Temperature Sensor Circuit Range/Performance (Bank 2 Sensor 2)
- P0423Heated Catalyst Efficiency Below Threshold (Bank 1)
- P0424Heated Catalyst Temperature Below Threshold (Bank 1)
- P0425Catalyst Temperature Sensor (Bank 1, Sensor 1)
- P0427Catalyst Temperature Sensor Circuit Low (Bank 1 Sensor 1)
- P0428Catalyst Temperature Sensor Circuit High (Bank 1 Sensor 1)
- P0429Catalyst Heater Control Circuit/Open (Bank 1)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.