Powertrain
generic / SAE
P0142
O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
The ECU detects an electrical fault in the heater circuit of the downstream oxygen sensor on bank 1. The heater current is out of range, suggesting an open or shorted heater element, blown fuse or wiring fault.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number1 / 42
Possible causes
- Sensor heater element open high
- Heater fuse blown medium
- Heater wiring or connector fault medium
Symptoms
- Check engine light on after several drive cycles
- Slightly increased fuel consumption during cold start
- Delayed entry into closed-loop fuel control
- Failed emissions inspection (lambda readiness)
Inspection / repair
- Difficulty: easy
- DIY: possible
- Estimated cost: 80–300 €
- Estimated time: 0.3–1.5 h
- Component: oxygen sensor b1s2
- Component: oxygen sensor heater fuse
- Component: oxygen sensor heater wiring
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012