P0031 — HO2S Heater Control Circuit Low (Bank 1 Sensor 1)
Category: Powertrain Severity: Low
Updated:
DTC code P0031 means: HO2S Heater Control Circuit Low (Bank 1 Sensor 1). It falls under the "Powertrain" category, with an estimated severity of Low. Common causes include open or shorted O2 sensor heater, blown fuse and heater wire broken or shorted to ground; it's worth confirming the diagnosis before replacing parts.
Possible causes
- Open or shorted O2 sensor heater
- Blown fuse
- Heater wire broken or shorted to ground
- Corroded connector
Symptoms
- Check engine light
- Higher fuel use on cold starts
- Possible emissions test failure
How to diagnose it step by step
- Measure heater resistance.
- Check fuse and supply.
- Inspect the wire near the exhaust (it may be melted).
- Replace the sensor.
How to fix it
It is almost always the upstream O2 sensor itself (burned heater). Confirm by measuring resistance and replace it.
Estimated repair cost
$100–300 with the sensor installed.
Frequently asked questions
What does DTC code P0031 mean?
HO2S Heater Control Circuit Low (Bank 1 Sensor 1).
Is code P0031 serious?
Severity Low. Usually a minor fault; check the causes listed.
Can I keep driving with code P0031?
Yes, you can drive without immediate risk.
Related codes
P0030 P0036 P0037 P0038 P0021 P0045 P0046 P0019 P0018 P0017
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