How do I know if my O2 sensor is bad?

A good O2 sensor oscillates between 0.1V and 0.9V rapidly. A lazy sensor responds slowly or gets stuck at one voltage.

Does P0130 affect gas mileage?

Yes — the upstream O2 sensor is critical for fuel trim. A bad one can cause 10-20% worse fuel economy.

Medium Severity

Emissions System

General fault with the upstream O2 sensor on bank 1. This sensor monitors exhaust oxygen to control fuel mixture.

Common Fix

Replace upstream O2 sensor bank 1

Estimated Cost (DIY)

$30 - $100

Faulty O2 sensorlikely

Exhaust leak before sensorpossible

Wiring damagepossible

Contaminated sensorpossible

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How do I know if my O2 sensor is bad?: A good O2 sensor oscillates between 0.1V and 0.9V rapidly. A lazy sensor responds slowly or gets stuck at one voltage.
Does P0130 affect gas mileage?: Yes — the upstream O2 sensor is critical for fuel trim. A bad one can cause 10-20% worse fuel economy.

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