Do V6 engines have 4 O2 sensors?

Yes — most V6 and V8 engines have 4 O2 sensors: upstream and downstream on each bank.

Which O2 sensor is most important?

The upstream sensors (sensor 1) are most important — they control fuel mixture. Downstream sensors only monitor the catalytic converter.

Low Severity

Emissions System

General fault in the downstream O2 sensor on bank 2.

Common Fix

Replace downstream O2 sensor bank 2

Estimated Cost (DIY)

$25 - $80

Faulty O2 sensorlikely

Wiring damagepossible

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Do V6 engines have 4 O2 sensors?: Yes — most V6 and V8 engines have 4 O2 sensors: upstream and downstream on each bank.
Which O2 sensor is most important?: The upstream sensors (sensor 1) are most important — they control fuel mixture. Downstream sensors only monitor the catalytic converter.

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