Powertrain
generic / SAE
P042C
Catalyst Temperature Sensor Circuit Low (Bank 1 Sensor 2)
Catalyst temperature sensor at bank 1 sensor 2 below lower plausibility — short to ground. 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.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / 2C
Possible causes
- Short to ground high
- Connector pins corroded - high contact resistance low
- Harness chafing through insulation low
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 60–500 €
- Estimated time: 0.5–2.5 h
- Component: exhaust temperature sensor
- MIL / check engine light
- emissions-relevant
Sources
References
sae:J2012