P0036
Low SeverityHO2S Heater Control Circuit (Bank 1, Sensor 2)
Emissions System
What Does P0036 Mean?
The heater circuit for the downstream (post-cat) O2 sensor on bank 1 has failed. This sensor monitors catalytic converter efficiency.
Common Fix
Replace downstream O2 sensor bank 1
Estimated Cost (DIY)
$25 - $80
Symptoms
- ⚠️Check engine light
- ⚠️Failed emissions test
- ⚠️No noticeable driveability issues
- ⚠️Possible false P0420 code
Related Symptoms
Common Causes
How to Diagnose P0036
- 1Check O2 heater fuse
- 2Inspect downstream sensor wiring for heat damage
- 3Measure heater resistance
- 4Replace sensor if heater open-circuit
OEM Diagnostic Flowchart
Scroll to load technician if/then branches.
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Related Resources
Repair guides, symptom pages, and wiring diagrams related to P0036.
OEM Manual Evidence
Browse →A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL Denali AWD V8-6.2L Service Manual | Operation CHARM Operation CHARM : Car...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL Denali 2WD V8-6.2L Service Manual | Operation CHARM Operation CHARM : Car...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL 4WD V8-6.0L Service Manual | Operation CHARM Operation CHARM : Car repair...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL 4WD V8-5.3L Service Manual | Operation CHARM Operation CHARM : Car repair...
Related Symptoms
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Exact Repair Workflows
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Open the exact repair flow most commonly associated with P0036 on this vehicle.
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Related Codes
Low voltage in the downstream O2 sensor heater on bank 1. The heater element has likely burned out.
The heater in the downstream O2 sensor on bank 1 has failed.
The oxygen sensor heater circuit on the upstream (pre-cat) sensor of bank 1 has a fault. The heater gets the O2 sensor to operating temperature quickly for proper fuel trim.
Frequently Asked Questions
- Does P0036 affect performance?
- No, the downstream O2 sensor only monitors the catalytic converter. You will not notice any driveability change.
- Can P0036 cause P0420?
- Yes, a faulty downstream sensor can give false P0420 readings. Fix P0036 first and see if P0420 clears.
Related Repair Guides
If your vehicle has triggered P0036, these DIY repair guides may help: