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Code

P0030

Emissions

HO2S heater control circuit — Bank 1 Sensor 1

The upstream O2 sensor heater control circuit has a fault.

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Most likely causes

Blown O2 heater fuse
Faulty sensor heater
Wiring fault

Symptoms you may notice

Check engine light
Slow warm-up to closed loop

Checks to run

Test heater circuit
Check fuse
Inspect wiring

Tools you may need

Multimeter

Always diagnose before replacing. Codes share symptoms; confirm the cause with measurements before buying parts.

Related codes in Emissions

Catalyst system efficiency below threshold — Bank 1

Oxygen sensor circuit malfunction — Bank 1 Sensor 1

Oxygen sensor heater circuit malfunction — Bank 1 Sensor 1

Oxygen sensor heater circuit malfunction — Bank 1 Sensor 2

Oxygen sensor circuit low voltage — Bank 1 Sensor 1

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