Code reader codes

My check engine light was on so I put my code reader on it and got a message that read "O2 sensor circit/ high volts (bank1 sensor1). I know that it's for a oxygen sensor but there are two. Does anyone know if this code tells me which one it might be? There is an upflow and downflow I think. Thanks

My check engine light was on so I put my code reader on it and got a message that read "O2 sensor circit/ high volts (bank1 sensor1). I know that it's for a oxygen sensor but there are two. Does anyone know if this code tells me which one it might be? There is an upflow and downflow I think. Thanks


bank 1 is always the side that the number 1 clyinder is on (driver side 1, 3, 5, 7) and sensor 1 is the upstream sensor meaning before catalytic converter.

Sensor 1 is the upstream one (before the cat). Sensor 2 is the downstream one (after the cat).

Bank 1 is always the side of the engine that has cylinder #1, assuming there are two banks on a vehicle. These vans only have one bank, so in your case you'll want to be checking out the O2 sensor before the cat, or it's wiring.

Does sound like it's the front O2. Of course this is the one that often fails and is the hardest to remove. It yours is stuck in the exhaust pipe, find a tall nut with the same threads and have a shop cut a hole and weld the nut nearby for the new O2 sensor.