P0037
Low SeverityHO2S Heater Control Circuit Low (Bank 1, Sensor 2)
Emissions System
What Does P0037 Mean?
Low voltage in the downstream O2 sensor heater on bank 1. The heater element has likely burned out.
Common Fix
Replace downstream O2 sensor
Estimated Cost (DIY)
$25 - $80
Symptoms
- ⚠️Check engine light
- ⚠️Failed emissions
- ⚠️No performance symptoms
- ⚠️Possible false cat efficiency code
Common Causes
Burned-out heater elementlikely
Open wire in heater circuitpossible
Corroded sensor connectorpossible
Blown fusepossible
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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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.