OBD-II FAULT CODE
P0142
O2 Sensor Circuit Malfunction (Bank 1 Sensor 3)
Meaning, symptoms, likely causes, diagnostic checks and repair guidance for P0142.
- Check Engine light
- Poor drivability or reduced fuel economy depending on fault
- Fuel economy may drop
- Faulty O2 sensor
- Heater circuit fuse/wiring fault
- Exhaust leak
- Engine running too rich/lean
- Scan all modules and record freeze-frame data before clearing codes
- Check battery voltage and related fuses
- Inspect O2 sensor wiring near exhaust heat
- Check heater power/ground and sensor response before replacement
- Repair wiring/fuse/exhaust leak or replace confirmed faulty oxygen sensor
Related Codes
Need more help?
Search manuals, wiring diagrams and technical service bulletins.
Not sure what to do next?
Get step-by-step instructions and professional repair information.
Disclaimer: Information is provided for general guidance only and may not apply to all vehicles. Always consult a qualified technician.