P0036
Low SeverityHO2S Heater Control Circuit (Bank 1, Sensor 2)
Emissions System
P0036 — Instant Answer
HO2S Heater Control Circuit (Bank 1, Sensor 2)
Severity: LOW SEVERITY
Meaning: The heater circuit for the downstream (post-cat) O2 sensor on bank 1 has failed. This sensor monitors catalytic converter efficiency.
Safe to drive? Usually yes with caution, but confirm root cause before long trips.
Estimated repair cost: $25 - $80
Most common causes:
- 1. Failed O2 sensor heater (35-45% of cases)
- 2. Wiring damage from exhaust heat (10-25% of cases)
- 3. Blown fuse (10-25% of cases)
- 4. Connector corrosion (10-25% of cases)
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 Procedures for P0036
HO2S Heater Control Circuit (Bank 1 Sensor 2) Found 58 OEM service manual procedures.
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
Showing 8 of 58 procedures
OEM Diagnostic Flowchart
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Parts & Tools for This Job
Common parts shoppers buy for P0036 HO2S Heater Control Circuit (Bank 1, Sensor 2).
Oxygen Sensor
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Catalytic Converter
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EVAP Purge Valve
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Gas Cap
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OBD2 scanner
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Check SpecificationsBattery tester
Check cranking and charging health before replacing expensive parts.
A weak battery can mimic alternator or starter problems.
Check SpecificationsMultimeter kit
Confirm voltage, continuity, and sensor power with one simple kit.
A meter is the cheapest way to rule out a bad circuit fast.
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Related Resources
Repair guides, symptom pages, and wiring diagrams related to P0036.
OEM Manual Evidence
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Diagnostic Trouble Codes (DTC) Index — 2013 Audi A3 Premium, 2.0L Eng VIN E, Automatic DCT Trans Service Manual ~ LEMON Manuals LEMON Manua...
Diagnostic Trouble Codes (DTC) Index — 2013 Audi A3 Premium, 2.0L Eng VIN E, Standard Trans Service Manual ~ LEMON Manuals LEMON Manuals: R...
Diagnostic Trouble Codes (DTC) Index — 2013 Audi A3 Premium, 2.0L Eng VIN E, Standard Trans Service Manual ~ LEMON Manuals LEMON Manuals: R...
Related Symptoms
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Exact Repair Workflows
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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.
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Author & Review
Published by AllOEMManuals, founded by Lyndon Bedford, an automotive technician with 20 years of experience. He owned and operated a mechanic shop in Hurst, Texas from 2014 to 2022 and continues hands-on repair work.
Content may combine manual references, general repair templates, and AI-assisted drafting. Confirm the source, vehicle configuration, and applicability before working. Report corrections through our contact page.
Last updated: 2026-10-29