P0037
Low SeverityHO2S Heater Control Circuit Low (Bank 1, Sensor 2)
Emissions System
P0037 — Instant Answer
HO2S Heater Control Circuit Low (Bank 1, Sensor 2)
Severity: LOW SEVERITY
Meaning: Low voltage in the downstream O2 sensor heater on bank 1. The heater element has likely burned out.
Safe to drive? Usually yes with caution, but confirm root cause before long trips.
Estimated repair cost: $25 - $80
Most common causes:
- 1. Burned-out heater element (35-45% of cases)
- 2. Open wire in heater circuit (10-25% of cases)
- 3. Corroded sensor connector (10-25% of cases)
- 4. Blown fuse (10-25% of cases)
Symptoms
- ⚠️Check engine light
- ⚠️Failed emissions
- ⚠️No performance symptoms
- ⚠️Possible false cat efficiency code
Related Symptoms
Common Causes
How to Diagnose P0037
- 1Check heater fuse
- 2Measure heater resistance (should be 2-30 ohms)
- 3Inspect wiring
- 4Replace sensor if heater is open
OEM Procedures for P0037
HO2S Heater Control Circuit Low (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 P0037 HO2S Heater Control Circuit Low (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 P0037.
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
The heater circuit for the downstream (post-cat) O2 sensor on bank 1 has failed. This sensor monitors catalytic converter efficiency.
The heater in the downstream O2 sensor on bank 1 has failed.
The O2 sensor heater circuit voltage is lower than expected on the upstream bank 1 sensor. Usually means an open circuit in the heater element.
Frequently Asked Questions
- What is the difference between P0036 and P0037?
- P0036 is a general heater circuit fault; P0037 specifically means the voltage is low (open circuit). Both usually need a sensor replacement.
- How long can I drive with P0037?
- Indefinitely — there are no driveability effects. However, it will cause emissions test failure.
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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