OBD-II code · Powertrain (generic)
P0438 Catalyst Temperature Sensor Circuit High (Bank 2 Sensor 1)
Catalyst temperature sensor at bank 2 sensor 1 above upper plausibility — open signal or short to B+.
Is it safe to drive with P0438?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen signal line
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
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
- P0428Catalyst Temperature Sensor Circuit High (Bank 1 Sensor 1)
- P042DCatalyst Temperature Sensor Circuit High (Bank 1 Sensor 2)
- P043DCatalyst Temperature Sensor Circuit High (Bank 2 Sensor 2)
- P0435Catalyst Temperature Sensor Circuit (Bank 2 Sensor 1)
- P0436Catalyst Temperature Sensor Circuit Range/Performance (Bank 2 Sensor 1)
- P0437Catalyst Temperature Sensor Circuit Low (Bank 2 Sensor 1)
- P0439Catalyst Heater Control Circuit/Open (Bank 2)
- P043ACatalyst Temperature Sensor Circuit (Bank 2 Sensor 2)
- P043BCatalyst Temperature Sensor Circuit Range/Performance (Bank 2 Sensor 2)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.