P0135
Oxygen sensor heater circuit malfunction (Bank 1 Sensor 1)
The ECU has detected a fault in the heater circuit for the upstream oxygen sensor on Bank 1.
What this code means
The ECU has detected a fault in the heater circuit for the upstream oxygen sensor on Bank 1.
Possible causes
- Failed oxygen sensor heater
- Blown fuse
- Open or short circuit in heater wiring
- Connector corrosion
- ECU driver fault
Common symptoms
- Check engine light
- Delayed closed-loop operation
- Possible increased fuel consumption
- Usually little change in driveability
Checks to make
- Check related oxygen-sensor codes
- Inspect the sensor connector and wiring
- Check heater circuit fuse where applicable
- Measure heater resistance and supply according to manufacturer data
Safety
- Exhaust components become extremely hot. Allow the exhaust to cool before inspecting sensors or wiring.
Model notes
Bank 1 Sensor 1 is normally the oxygen sensor before the catalytic converter on the cylinder bank containing cylinder 1.