[aaronblack]

Excuse my ignorance, never have changed a lambda probe before, I've a 2C9F code in INPA and P0056 on a generic code reader.

I understand the code is BANK 2 meaning cyl 3, 5 & 6 and its post cat! But isn't their 2 probes post cat? How would you know which it is to replace?

There are 4 probes in total according to RealOEM:

[IllSic_Design]

That would be the o2 sensor at the bottom/rear of the down pipes and the one located towards the outside of the vehicle.

[therealdb1]

The only difference between the two post-cat sensors will be the length of the wire but to be honest they will not do a great deal on a UK based E92 anyway. The mixture will be controlled by the two pre-cat lambda sensors and the post-cat jobbies will tell you if the cats are working or not.

Probably different in California though. Some US States have tighter emissions controls than we have. In fact I read somewhere that OBDII was originally developed so that folk could drive cars in Florida since open loop systems could not meet their emissions requirements.

[Andystobbs]

You trace the exhaust pipework from cylinders in bank 2

[aaronblack]

I assume it's number 3 or 4 whichever is bank 2! Cheers for the help

[therealdb1]

Yes, sorry should have answered your question.

It will be 3 or 4. Easiest way to check is to follow the exhaust pipe from the rear 3 cylinders as Andystobbs says but if you want to order the probe before climbing under the car get the one with the longer wire and a cable tie!

Where will you buy the lambda probe from? Someone like Cheltenham will give you a discount on a genuine BMW part if you mention this forum and will also be able to confirm the correct sensor if you give them your chassis number.

[aaronblack]

Originally Posted by therealdb1

Yes, sorry should have answered your question.

It will be 3 or 4. Easiest way to check is to follow the exhaust pipe from the rear 3 cylinders as Andystobbs says but if you want to order the probe before climbing under the car get the one with the longer wire and a cable tie!

Where will you buy the lambda probe from? Someone like Cheltenham will give you a discount on a genuine BMW part if you mention this forum and will also be able to confirm the correct sensor if you give them your chassis number.

Cheers 👍, I'll contact Cotswold and see what they will offer.

[aaronblack]

Got quoted £178 for the sensor! Not sure but it does seem a little on the high side considering eBay/amazon sellers are selling these for £60-90 last time I checked.

[Tambohamilton]

I'd trust the eBay/Amazon probe about as far as I could throw it...and I've not got a good throwing arm!

Buy cheap, buy twice. Especially true with sensitive electronics like lambda probes.

[Andystobbs]

Originally Posted by aaronblack

Got quoted £178 for the sensor!

From a dealer, you will do. Buy Bosch from your local motor factor.

[aaronblack]

So I realised the only difference between a Bosch and BMW Bosch sensor is that BMW uses a proprietary connector.

So long story short, rather than spending £178, I bought a genuine Bosch sensor p/n 0258010413 for £42 and soldered my old connector onto it.

Thought I share this, incase its helpful to somebody.