O2 Sensor Problem - Please Help!

[ElliotStvnsn]

Hello all,

Firstly, I hope you've had a good Christmas, and I wish you a happy new year!

Now, I'm in a bit of a predicament and, not being too handy, would love some advice.

I'm currently driving a 2005 e85 2.0l and my engine warning light has come on. Looked at the code and it was an o2 sensor. No big deal, got it changed by the mechanic and my warranty covered it. A few weeks later, the engine light is on again and it's the other 3 o2 sensors... Take it back to the mechanic and he says it's looking like it'll be around £400 to fix it, and he's unsure if my warranty will payout this time. Being a family friend, he did try to order some from EuroParts but said they didn't fit so would have to contact BMW in the new year for parts.

Before he does this, can anyone point me in the direction of cheaper o2 sensors? Being on the Facebook forums it looks as though a few pilots are using Bosch sensors - would these be alright for my 2.0l too? If so, can someone tell me which I'd need?

As you can probably recognise, I could do with pointing (shoving) in the right direction.

Cheers all!

 

[tug]

Welcome to the forum mate, what codes did you get? The 2.0 is notorious for the emissions light (the yellow engine symbol) i should know i have the same as you for six years now :lol:

There could be other reasons why the light keeps coming on such has a cracked manifold, air leak from perished rubber hoses etc.

Before you go to a lot of expense, buy yourself a cheap obd 2 reader which can turn the light out. But have the zed checked for the above scenarios and if all is ok then dont worry too much.

Even if the manifold IS cracked its not that bad. These can be TIG welded for not much money

And you will find that what ever you do the pesky light will still come on randomly :roll:

The N46 likes to be driven hard. So what i do is drive taking it up to at least 4000 revs through the gears when possible & this will keep it "clear" so to speak. I still get the light come on randomly but i just plug in & turn out.

The code is always P402 catalyst below threshold bank 1.

I once had my local BMW indie check the emissions while the light was on & it would sail through the MOT.

Cheers, tug

 

[Z4paul]

Welcome to the forum mate, what codes did you get? The 2.0 is notorious for the emissions light (the yellow engine symbol) i should know i have the same as you for six years now :lol:

There could be other reasons why the light keeps coming on such has a cracked manifold, air leak from perished rubber hoses etc.

Before you go to a lot of expense, buy yourself a cheap obd 2 reader which can turn the light out. But have the zed checked for the above scenarios and if all is ok then dont worry too much.

Even if the manifold IS cracked its not that bad. These can be TIG welded for not much money

And you will find that what ever you do the pesky light will still come on randomly :roll:

The N46 likes to be driven hard. So what i do is drive taking it up to at least 4000 revs through the gears when possible & this will keep it "clear" so to speak. I still get the light come on randomly but i just plug in & turn out.

The code is always P402 catalyst below threshold bank 1.

I once had my local BMW indie check the emissions while the light was on & it would sail through the MOT.

Cheers, tug

Bloody hell, i could have said exactly the same Tug. We have had the same experience with the 2.0 but as you say, s change in driving style, using the rev range as you suggest worked for me.
I would also try something called Cataclean, suggested by Mr Tidy and certainly seems to have helped. I was panicking about sensors/cracked manifolds etc but it can be a much simpler fix.
Good luck with this

 

[colb]

Always go for oem parts when changing important sensors, O2 sensors have two circuits one is a heating circuit the other the circuit that measures what it is seeing in the exhaust. More often than not its the heating circuit that goes bad. A decent code reader should show which fault they have. Pattern sensors will most likely be supplied with a wiring kit to make the connections to the car, oem ones will have the correct plug to fit into the cars wiring.
Before paying out on new parts a check of all rubber hoses and intake bellows on the engines vaccum system needs checking for holes and splits, these will affect the fueling of the car and cause errors with O2 sensors often triggering codes, same for Maf sensors.

 

[ElliotStvnsn]

Always go for oem parts when changing important sensors, O2 sensors have two circuits one is a heating circuit the other the circuit that measures what it is seeing in the exhaust. More often than not its the heating circuit that goes bad. A decent code reader should show which fault they have. Pattern sensors will most likely be supplied with a wiring kit to make the connections to the car, oem ones will have the correct plug to fit into the cars wiring.
Before paying out on new parts a check of all rubber hoses and intake bellows on the engines vaccum system needs checking for holes and splits, these will affect the fueling of the car and cause errors with O2 sensors often triggering codes, same for Maf sensors.

Brilliant, thanks! Another question, could I use o2 sensors from 2.2l-3.0l for my 2.0l? Or would they fail?

 

[colb]

If you go to the oem parts site and enter your last seven letters and digits of your cars Vin number you will be presented with the parts listing for your actual car. Go find the exhaust lambda sensors and compare their part numbers they will have different part numbers due to the different cable lengths they come with in order to reach the connections alongside the rocker cover, clicking on the individual part numbers will take you to a new page where it will list all the other vehcles that part is fitted to.
https://www.realoem.com/bmw/enUS/showparts?id=BZ12-EUR-06-2005-E85-BMW-Z4_20i&diagId=18_0603

 

[tug]

Personally, i dont think it is the lambda's thats failed. Very unusual that all 4 have failed within a short period of time :scratchhead: If they have then something drastic has caused it, but what?

OP what codes are you getting?