What it means
The control circuit for the heater in the Bank 1 Sensor 2 heated oxygen sensor has a malfunction.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The downstream oxygen sensor after the catalytic converter on bank 1 has a heater that helps it reach its working temperature. The module monitors this heater circuit and sets P0036 when it detects a fault, which can delay downstream exhaust monitoring and contribute to increased emissions or poor fuel economy.
Common causes
Most likely first.
- Heater element open
- Heater fuse blown
Symptoms
- Check engine light on
- Increased emissions
- Reduced fuel economy
- Failed emissions test
How to diagnose it
- Record freeze-frame data and check for other oxygen-sensor heater codes to see whether the fault is limited to bank 1 sensor 2.
- Locate the downstream bank 1 sensor after the catalytic converter and inspect its connector and wiring for heat damage, disconnection, or corrosion.
- Check the heater fuse and circuit supply using the vehicle wiring diagram.
- Test the sensor heater and its control wiring for an open or poor connection using the manufacturer's procedure.
- If the wiring and fuse are sound, test the downstream sensor heater and module control to identify the failed part.
Common fixes
- Reconnect the bank 1 sensor 2 heater connector and secure the harness away from the exhaust.
- Replace a blown heater fuse after checking for the cause of the failure.
- Repair damaged wiring or corroded connector terminals.
- Replace the downstream bank 1 oxygen sensor if its heater element has failed.
Can I keep driving?
The vehicle is usually drivable if it runs normally, but emissions monitoring may be affected and fuel economy can decline. Repair it soon, particularly before an emissions test.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.