02 sensor

[Onkar02]

which sensor is bank 1, sensor 1 ? the one in the engine bay or the one below the car ? on my 03 lancer es

[cfdfireman1]

Q: which sensor is bank 1? A: there is only one bank.
Q: which sensor is sensor 1? A: AHHHH the first one.

[Onkar02]

under the car or in the engine bay ?

[cfdfireman1]

which one sees the exhaust first? that's #1

[doctorjon]

The one your talking about is located inside the exhaust manifold. The 1st o2 sensor is the one you really need. The second o2 is located inside your cat converter.

[Onkar02]

thanks for the help guys