Simple fool proof way to identify Bank1 and Bank2 side

Question

Is there a simple and fool proof way to locate which "side" of the engine Bank1 or Bank2 is on, with reference to OBDII data?

For example, you read ODBII live data and find that Bank2 Sensor2 (downstream) O2 sensor is not stable, but Bank1 Sensor2 is (duel exhaust vehicle). How can I determine for sure that the CAT on the left exhaust is bad or visa-versa?

Note this is not a question about checking the CAT (pressure test, temperature test, etc). This is about figuring out - by just looking in the car engine bay (?) which side is bank1 and which is bank2. Is this possible?

Solar Mike · Answer

You need to refer to the manufacturer's manual as I have never seen that information shown under the bonnet - but there may be a manufacturer that does provide it.

Zshoulders · Answer

Unfortunately, no. It depends on the car. Typically, bank 1 is the driver side, but this isn't true in all cases. For example, BMW E38 7 series has bank 1 on the passenger side. This data is not stored as a regular value in OBD-II.

You will need to research which side is bank 1 for the particular car in question.

Terry Gould · Answer

Unplug one of the oxygen or EGT sensors and a open circuit fault bankX will appear. You can use that to determine what side is what.

WildTigress4 · Answer

The way I was taught, is that bank 1 coincides with the side of the engine
where the #1 cylinder is.  So, if your firing  order on your spark plugs and wires (which go to the cylinders) starts 1 - 2 - 3 on the passenger side,(like my 1999 Ford F-150 V6 automatic), then the passenger side is bank 1, therefore the driver's side if the engine would be bank 2.

Simple fool proof way to identify Bank1 and Bank2 side

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