The heated oxygen sensor on bank 1 is the downstream sensor 2 behind the (first) catalytic converter, used mainly to monitor the converter. Its heating element brings it quickly to operating temperature. Typically the heater receives battery voltage via a fuse, and the engine control module switches the ground side with a pulsed signal while checking that the circuit state matches the command. P0036 is the general circuit fault: the measured state of the heater circuit does not fit the command, most often because the circuit is interrupted. Which physical fault sets the general, low or high code is defined by each manufacturer. Without heating, the sensor becomes ready late and catalyst monitoring may not complete.
Low severity. Can I keep driving?Yes, you can keep driving normally, because this sensor has little effect on how the engine runs. Schedule the repair, because with the light already on you will not notice any new faults that appear.
Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank. Sensor 2 is the sensor after the catalytic converter.
Symptoms
- Check engine light on
- Usually no noticeable drivability problem
- Catalyst monitor does not complete
- Emissions test or readiness check failed
Most likely causes
- Heating element inside the sensor burnt out
- Wire or connector damaged by heat or road spray
- Heater fuse blown; a shared fuse can set several heater codes
- Output driver or software of the engine control module
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P0036 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 0: Subsystem depends on the code range
- 36: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0036?
Yes, you can keep driving normally, because this sensor has little effect on how the engine runs. Schedule the repair, because with the light already on you will not notice any new faults that appear.
What causes code P0036?
The most common causes are: heating element inside the sensor burnt out; wire or connector damaged by heat or road spray; heater fuse blown; a shared fuse can set several heater codes.
Related codes
- P0037HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
- P0038HO2S Heater Control Circuit High (Bank 1 Sensor 2)
- P0056HO2S Heater Control Circuit (Bank 2 Sensor 2)
- P0054HO2S Heater Resistance Bank 1 Sensor 2
- P0141O2 Sensor Heater Circuit Bank 1 Sensor 2
Sources
- law.cornell.edu: 13 CCR 1968.2
- saabwisonline.com: dtc p0030 p0031 p0032 p0036 p0037 or p0038 without
- saabwisonline.com: dtc p0036 p0037 p0038 or p0141 ldk with turbocharg
- static.nhtsa.gov: MC 10080421 7690
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.