oxygen sensor?
 

Hello again,

I have a question. My car computer was scanned a little while ago and I was told I need a bank 1 oxygen sensor. Apparently this is why my check engine light is on.

I have two questions.
Does this affect my fuel economy?
How do I replace and where is it located?

Thanks
Brad

Yes it will affect fuel economy. It will be a plug in your exhaust with a wire sticking out of it.

I can't remember if it's before or after the cat for OBDII cars but you should be able to spot it right away.

You'll need an open end wrench and thats about it, once it's out follow the wire up to a circle connector and twist it out. Install is just a reversal of those steps.

You've also got to figure out which bank it is, There are two on the 540i so it can be the right one or the left one.

standard obd2 reader
 

Thanks for the info

Would a standard obd2 computer tell me what bank?

All I was told was that it was bank 1

You have 4 sensors, 2 pre-cat, 2 post-cat. Last I checked, pre-cat was about $40 and post-cat around $90. Post-cat is essentially the same sensor as the former, but with a longer wire. They're made by Bosch. The stealer marked the backs up by like 3 or 4 times. StealMW Mississauga wanted $320 for each back when I needed them a few years ago.

where
 

Where do you get them for that price?

Prices for the before CAT and after CAT O2 Sensors:

http://www.autopartsway.ca/autoparts...MW~540i~240666

You're a do it yourselfer, so I don't know. Techmax in Mississauga did them for me at that price plus labour about 3 yrs ago. I don't know what today's prices are, but I can't see them changing that much. Bosch has a factory/office around Derry/Creditview. I called them at the time but they only deal wholesale. Too bad.

Oh and by the way, back in the day, BMW used to sell the sensors in BMW boxes. The last bunch of years they didn't give a shit. You get the same Bosch sensors in the same Bosch box for three times the price! LOL

I am going to try and locate someone in Durham. Thanks for all the info!

NP. Good luck.

Check Amazon.com
 

Out of all places, these sensors are cheapest on Amazon.com
Make sure you get the correct sensors for your '97 model year.
I would do all of them, while you're at it.