Drive with caution — fix soon.
This code means the upstream oxygen sensor on bank 1 is sending a voltage signal that's too high, which usually indicates a rich air-fuel mixture or a fault in the sensor circuit. It can be caused by a failing oxygen sensor, wiring shorted to power, a leaking fuel injector, or excessive fuel pressure. Repairs often involve replacing the sensor or fixing the wiring, though a rich-running cause may need further diagnosis.
$150 – $500
Varies by vehicle and root cause.
Usually yes in the short term, but don't delay too long. A rich mixture can foul plugs and harm the catalytic converter over time, so get it diagnosed and repaired soon.
Typically $150 to $500. Replacing the oxygen sensor plus labor is the most common cost, while a fuel injector or pressure issue causing the rich condition can cost more to fix.
It's moderate severity. The car still runs, but the rich mixture wastes fuel and can damage the catalytic converter if left unaddressed, so it's worth fixing promptly.
Not always. A high-voltage reading can come from the sensor itself, but it can also reflect a genuinely rich fuel mixture caused by a leaking injector or high fuel pressure, so the cause needs to be confirmed.