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
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Related Resources
Repair guides, symptom pages, and wiring diagrams related to P0037.
Related Symptoms
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Open the exact repair flow most commonly associated with P0037 on this vehicle.
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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
Written by AllOEMManuals Editorial Team. Reviewed by ASE-certified technicians and updated with factory-reference checks for fitment-sensitive steps.
This guide was drafted with AI assistance and reviewed for accuracy by a human editor.
Last updated: 2026-05-07