P0036: O2 Sensor Heater Control Circuit — Bank 1 Sensor 2
What to do
No driveability impact, but the catalyst monitor cannot complete, so the car will not pass an emissions test. Have the connector inspected before the sensor is replaced.
What this code means
A heater circuit fault on the bank 1 downstream sensor — the one after the catalytic converter, whose job is to grade the converter's performance rather than to trim fuelling. Because it sits under the car rather than in the engine bay, its harness suffers road salt and stone damage far more than the upstream sensor's does, and corrosion at the connector is the single most common cause.
Likely causes
Start here
- Corroded or loose connector · easy
- Failed oxygen sensor heater element · easy
- Road damage to underfloor wiring · moderate
Less common
- Blown fuse supplying the heater circuit · easy
- Open circuit in heater wiring · moderate
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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