O2 sensors after cat?

L

lee1981

Member
Hi Gents/Ladies,

O2 sensors after the cat I think (bank 2??) has caused my EML to show on the dash.

I've had 1 replaced by my local garage and still have the light showing to which they told me is due to the fact that there are two sensors. Is this correct? I've been to the garage for years so don't think they would dupe me.

I was with him when he had the reader plugged in and it looked like there was 2x sensors in bank 1 and 2x sensors in bank 2. Both the bank 2 sensors appeared to have no voltage change while the car was running/revved. Again does this sound correct or am I boss eyed?

Was wondering if it was an easy enough job for myself to do?

Thanks for reading,

Lee.
 
Hi, you have 1 precat and 1 postcat sensor on each bank, if you change one yourself you're going to need a special ring spanner with a cut-out for the lambda wire.
Rob
 
Yes OP. Get the code cleared and see if it re-appears before your wallet gets emptied!

The EML on my Z4 lit up amber a couple of weeks ago so I took it to my local specialist indy last week and it seems it had flagged bank 2 O2 sensor, Inlet Camshaft Vanos solenoid and faults on both cats, but they cleared the fault codes and the EML light is still out (for now at least) - crossing my fingers!

TBH I'm thinking about buying an OBD lead for next time as I also have an E46 as a daily, and we have another E46, an R53 Mini and an R56 Mini in the family so it could prove very useful!

Any recommendations would be gratefully received!
 
Mr Tidy said:
Yes OP. Get the code cleared and see if it re-appears before your wallet gets emptied!

The EML on my Z4 lit up amber a couple of weeks ago so I took it to my local specialist indy last week and it seems it had flagged bank 2 O2 sensor, Inlet Camshaft Vanos solenoid and faults on both cats, but they cleared the fault codes and the EML light is still out (for now at least) - crossing my fingers!

TBH I'm thinking about buying an OBD lead for next time as I also have an E46 as a daily, and we have another E46, an R53 Mini and an R56 Mini in the family so it could prove very useful!

Any recommendations would be gratefully received!
Click to expand...

If you an android phone just get a Bluetooth eml327 dongle and the torque app. You can reset easily then for under a tenner for both.

Should be able to do the same with an iPhone as well.
 
Hi Mr Tidy.
This is really good for a simple EOBD reader with live data capability http://www.ebay.co.uk/itm/2016-New-Autel-MaxiScan-MS509-OBDII-EOBD-Auto-Code-Reader-Car-Scanner-Diagnostic-/252429550334?hash=item3ac5f942fe:g:HagAAOSw-W5Uti2g

Hi Lee.
Before any o2 sensors are changed the wiring integrity has to be checked. There are 2 heater wires, a signal ground and the signal wire itself. Any good garage can quickly check those.
You don't necessarily need a special socket. You can cut the wire to the old o2 sensor and use a deep reach socket (22mm???) and then put the new one in using a ring or open ended spanner.

Good luck with your adventure!
Andy.
 
Hi Gents,

Thanks for getting back to me so quickly! I should have mentioned that I have an OBE reader and have cleared the fault. Second turn off the key though and the fault comes back.

What confused me was what they mean by bank one and two? I take it that the exhaust splits where the sensors are hence the need for two? Its the only fault that is showing.

Regards,

Lee.
 
lee1981 said:
Hi Gents,

Thanks for getting back to me so quickly! I should have mentioned that I have an OBE reader and have cleared the fault. Second turn off the key though and the fault comes back.

What confused me was what they mean by bank one and two? I take it that the exhaust splits where the sensors are hence the need for two? Its the only fault that is showing.

Regards,

Lee.
Click to expand...

Not sure what engine you have as not looked through the posts (sorry). On the 3.0si the exhaust manifold takes three cylinders each. Front three, bank one, goes down its own exhaust pipe as it were and the back three, bank 2, have their own. Bit of a rubbish description but I hope it makes sense. Basically you have two post cat sensors, one in each bank and two pre cat sensors, one in each bank.
 
andyfanshawe said:
Hi Mr Tidy.
This is really good for a simple EOBD reader with live data capability http://www.ebay.co.uk/itm/2016-New-Autel-MaxiScan-MS509-OBDII-EOBD-Auto-Code-Reader-Car-Scanner-Diagnostic-/252429550334?hash=item3ac5f942fe:g:HagAAOSw-W5Uti2g
Click to expand...

Many thanks for that Andy - I may need one pretty quick, as the Amber EML reappeared tonight! :evil: So that didn't quite last a week! Still at least the power steering leak on my E46 got fixed today - just in time!

I'm a bit stone age tech-wise, so my phone is neither Apple or Android. :lol: (It does calls and texts, which is all I really want it for).

So just one question, would the code reader you recommended work with a notebook PC?

Much appreciate your help - but that is what this forum does so well.

Cheers, Iain.
 
Hi Iain.
The code reader plugs into the 16 pin socket under the dash on the drivers side. Doesn't need any phone or notebook/PC.
Bear in mind its only an EOBD reader. Will give you engine management live data and codes, but wont go into any other modules or give manufacture specific codes. very good for diagnosing emissions data like o2 sensors etc.
Must be a video on youtube on it!!

Andy.
 
That's brilliant and I get what you mean Roundozo, was perfectly clear enough.

I think I'm going to start flicking through the Haynes manual I have to get a bit more of an understanding though most of it only covers the 3 series I've noticed. :-/

Cheers again.

Lee
 
I've just had one go, e85 3.0, bank 1 after cat, took it into Darren Woods to confirm what my code reader was saying, quoted me £170 fitted for a bosch one , the gen bmw part is £160 + vat, just to buy, ouch!
However they reckon it wont effect anything as it is after the cat????.
So for the time being ij gonna leave it and monitor the situation,
M
 
Mine had gone after the cat, bank 2 and although power and driveability stayed the same my mpg dropped slightly. I also swear it was depositing more black carbon marks in the exhaust. Possibly due to over fueling.

You can get them cheaper. Don't buy aftermarket stuff for sensors etc as they usually don't work. I however refused to pay £160 so searched around. Using the wonderful powers of the internet I found a Bosch parts wholesale place. Gave them the part number and paid about £100 in the end if I remember correctly.

Also, don't know if you are aware but RealOEM is a very useful website. You can break your car down to individual components, see where they are and also get part numbers. Well worth a gander if you've not been there before.
 
I had the same thing, BMW specialists quoted me £190 Inc vat + labour I think it was.
My local garage quoted £83 + vat and it somehow came out at £130 including labour! Must have been mate rates! :-D

Definitely going to check out RealOEM though because they said that there was 3 or 4 variants of the sensors and that they wouldn't know which one it was until they removed mine.

Cheers again.

Lee
 
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