OBD2 Car ScannerWhat does P0142 mean?
P0142 stands for 02 Sensor Circuit Malfunction (Bank 1 Sensor 3). The engine computer has found a problem with how fuel and air are measured or mixed. This affects fuel economy, emissions and sometimes how smoothly the engine runs.
Powertrain codes cover the engine, transmission and emissions. When the car's computer sees a reading outside its normal range, it stores this code and may turn on a warning light on the dashboard.
Common causes
- Vacuum or intake air leaks
- Dirty or faulty mass airflow (MAF) sensor
- Faulty oxygen sensor or its wiring
- Fuel pressure problems (pump, filter or regulator)
- Clogged or leaking fuel injectors
What to do
- Read all stored and pending codes with a scanner. Several codes together often point to one cause.
- Note the freeze frame data (speed, temperature, load) recorded when the code was set.
- Inspect the wiring and connectors of the part named in the code for damage, corrosion or looseness.
- Fix the most likely and cheapest cause first, then clear the code and drive to see if it comes back.
Read this code from your own car
Plug in a cheap ELM327 adapter and the app shows every fault code, what it means and how to fix it.
Frequently asked questions
What does P0142 mean?
P0142 means “02 Sensor Circuit Malfunction (Bank 1 Sensor 3)”. It belongs to the fuel and air metering group: The engine computer has found a problem with how fuel and air are measured or mixed. This affects fuel economy, emissions and sometimes how smoothly the engine runs.
Is it safe to drive with P0142?
You can usually drive carefully for a short time, but fix it soon to avoid further damage or higher fuel use.
How do I clear P0142?
Fix the cause, then clear the code with an OBD2 scanner or app. If the fault is still there, the code will come back.
Related codes
- P013EO2 Sensor Delayed Response - Rich to Lean (Bank 1 Sensor 2)
- P013FO2 Sensor Delayed Response - Lean to Rich (Bank 1 Sensor 2)
- P014002 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)
- P014102 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
- P014302 Sensor Circuit Low Voltage (Bank 1 Sensor 3)
- P014402 Sensor Circuit High Voltage (Bank 1 Sensor 3)
- P014502 Sensor Circuit Slow Response (Bank 1 Sensor 3)
- P014602 Sensor Circuit No Activity Detected (Bank 1 Sensor 3)
Code meanings can vary by manufacturer. This page is general guidance, not a repair manual. Always confirm the cause before replacing parts.