[mrbensam]

Thought I would make a quick post about replacing one of my 02 sensors

My power delivery was a bit rough and when idling the engine would rock almost like a misfire and the engine sounded rougher than my brothers does

After scanning my car with ISTA I had 2 codes for the pre cat 02 sensor - 287500 and 287100 both relating to the pre cat 02 sensor

After clearing the codes a few times they kept coming back. I used one of the functions in ISTA to test it and it revs your engine a bit and shows you a few fancy graphs and basically confirmed it was faulty



I replaced it quite easily after cutting my hands to bits haha. After replacing it I cleared all the adaptations using ISTA because it tells you to do so

Now the car doesn’t shake when idling and the power delivery is also 1000 times smoother. If you have the same issue maybe this post will help you. I couldn’t find anything about this so thought I would share my experience 🫡

[TurboWeasel]

Good stuff. I thought it would be covered in oil from your other thread, so maybe not the turbo then.

[mrbensam]

Originally Posted by TurboWeasel

Good stuff. I thought it would be covered in oil from your other thread, so maybe not the turbo then.

So did I mate haha, I still have no idea where my oil is going. I'm just topping it up and hoping for the best at the moment! Indy garage did say they couldn't see any oil in the exhaust or downpipe so fuck knows whats going on

[TurboWeasel]

Originally Posted by mrbensam

So did I mate haha, I still have no idea where my oil is going. I'm just topping it up and hoping for the best at the moment! Indy garage did say they couldn't see any oil in the exhaust or downpipe so fuck knows whats going on

Gotta be the valve guides/seals or piston rings then Shame it's not easy to get a borescope into a diesel engine as you would soon see what's what!
N57s don't normally suffer from cylinder wall scoring though unless an injector has failed and bore washed it for 1000s of miles.

See if your indy can do a leakdown test for you.

[AB02AYD]

Originally Posted by mrbensam

Thought I would make a quick post about replacing one of my 02 sensors

My power delivery was a bit rough and when idling the engine would rock almost like a misfire and the engine sounded rougher than my brothers does

After scanning my car with ISTA I had 2 codes for the pre cat 02 sensor - 287500 and 287100 both relating to the pre cat 02 sensor

After clearing the codes a few times they kept coming back. I used one of the functions in ISTA to test it and it revs your engine a bit and shows you a few fancy graphs and basically confirmed it was faulty



I replaced it quite easily after cutting my hands to bits haha. After replacing it I cleared all the adaptations using ISTA because it tells you to do so

Now the car doesn’t shake when idling and the power delivery is also 1000 times smoother. If you have the same issue maybe this post will help you. I couldn’t find anything about this so thought I would share my experience 🫡

Don't suppose you've got a how-to guide? Facing the same issue on my 435D with a 287500 code and a bit of shuddering between 1000-1500rpm. Can get hold of the part but not so sure about finding the old one, removing and replacing.

[TurboWeasel]

It's the first sensor in the DPF, right next to the turbo housing. Just remove the old one and stick the new one in.

[mrbensam]

Originally Posted by AB02AYD

Don't suppose you've got a how-to guide? Facing the same issue on my 435D with a 287500 code and a bit of shuddering between 1000-1500rpm. Can get hold of the part but not so sure about finding the old one, removing and replacing.

I bought an 02 sensor socket to remove it but it’s fairly simple! The hardest part is unplugging the cable

[TurboWeasel]

Hi mate, where is the testing procedure bit in ISTA? I had a look today and couldn't find it.

Mine's just started stuttering with medium pedal between 1500-1800rpm and intermittent lumpy idle, and it has no power unless flooring it. Thought it was the classic jammed EGR valve issue but I checked that and it looks brand new and moves freely, so they must have replaced it in the recall.

Sure enough, in the ista DDE module there's a 287100 fault code for the pre cat lambda sensor. Annoying as Bimmerlink doesn't show it, which is really useless when diagnosing away from home!

Yeah I can see where the wiring is routed it's hand shredding territory! Did you use a crow's foot type lambda socket, or the long straight one, just so I know which type to get?

[mrbensam]

Originally Posted by TurboWeasel

Hi mate, where is the testing procedure bit in ISTA? I had a look today and couldn't find it.

Mine's just started stuttering with medium pedal between 1500-1800rpm and intermittent lumpy idle, and it has no power unless flooring it. Thought it was the classic jammed EGR valve issue but I checked that and it looks brand new and moves freely, so they must have replaced it in the recall.

Sure enough, in the ista DDE module there's a 287100 fault code for the pre cat lambda sensor. Annoying as Bimmerlink doesn't show it, which is really useless when diagnosing away from home!

Yeah I can see where the wiring is routed it's hand shredding territory! Did you use a crow's foot type lambda socket, or the long straight one, just so I know which type to get?

Hello mate, I honestly can’t remember where it is.. I think I just typed in 02 sensor on the search thing on ISTA and found the test. It runs some sort of test and shows you some fancy graphs!

I ordered a specific 02 sensor socket and used that and it was an easy job really! It has a little cut out for the wire and you just use a ratchet

Hardest part was disconnecting the wiring.. definitely had a few cuts on my hands after that! There is another connector nearby that you can unbolt to give you easier access.. you will see what I mean when you do it!

Mine was idling a bit rough and replacing the sensor solved it.. code never came back either!

[TurboWeasel]

Cheers buddy. My local screwfix had those O2 sensor sockets, so grabbed one this morning.

I reset the DDE adaptations yesterday and it drove absolutely perfect for an hour this morning, ffs I'm slightly concerned the fault code was a symptom and not the cause now, but oh well, I'll shove the sensor in tomorrow anyway, especially as I picked up the sensor from the dealer this morning - £293

Cheers for the tips

[mrbensam]

Originally Posted by TurboWeasel

Cheers buddy. My local screwfix had those O2 sensor sockets, so grabbed one this morning.

I reset the DDE adaptations yesterday and it drove absolutely perfect for an hour this morning, ffs I'm slightly concerned the fault code was a symptom and not the cause now, but oh well, I'll shove the sensor in tomorrow anyway, especially as I picked up the sensor from the dealer this morning - £293

Cheers for the tips

Wow I would take that back if I was you!! You can get the Bosch one from GSF for £100

[bishbosh]

Yep, think I paid about £90, it's been fine ever since.

[TurboWeasel]

All done. Wasn't too bad swapping it tbh

Reset all the DDE adaptions again (always a good idea with new sensors) and it's mega now. Quite a shocking difference actually! Feels like a different engine and the gearshifts are like butter now that the DDE can actually calculate engine load properly.

Yeah I know the dealer sensor was silly money but I needed one quickly as it's my daily, and it's the only one I could get on a Saturday morning.

[mrbensam]

Originally Posted by TurboWeasel

All done. Wasn't too bad swapping it tbh

Reset all the DDE adaptions again (always a good idea with new sensors) and it's mega now. Quite a shocking difference actually! Feels like a different engine and the gearshifts are like butter now that the DDE can actually calculate engine load properly.

Yeah I know the dealer sensor was silly money but I needed one quickly as it's my daily, and it's the only one I could get on a Saturday morning.

Isright mate, glad it worked out! ISTA tells you to reset adaptations after fitting new sensor so you’re bang on

[TurboWeasel]

Originally Posted by mrbensam

Isright mate, glad it worked out! ISTA tells you to reset adaptations after fitting new sensor so you’re bang on

I just noticed on your screenshot it tells you to check the sensor for soot contamination. Mine was pretty crudded up to be fair, so maybe it just needed a clean

[ushafiq]

Hi
A quick help on this topic please!
Question: does anyone who have replaced their pre cat O2 sensor, had sooty exhaust?
My car (435xd) drives just fine - no EML ever or a limp mode but definitely, recently notting that exhaust stays very sooty now - I have always used premium fuel, with oil changes after 5k miles - Odometer reading is at 67k. Car consume no oil. I checked via Bimmerlink app and there are no fault codes related to O2 sensor. In my mind, based on process of elimination, I am planning to change both pre and post cat O2 sensors to see if this solves my issue. DPF is regenerating as normal- haven’t seen any sign I can’t change in the mpg - this sooty exhaust is just bothering me a lot. I recall the exhaust used to stay absolutely clean but not anymore!
Any help would be appreciated
Thanks

[TurboWeasel]

Originally Posted by ushafiq

Hi
A quick help on this topic please!
Question: does anyone who have replaced their pre cat O2 sensor, had sooty exhaust?
My car (435xd) drives just fine - no EML ever or a limp mode but definitely, recently notting that exhaust stays very sooty now - I have always used premium fuel, with oil changes after 5k miles - Odometer reading is at 67k. Car consume no oil. I checked via Bimmerlink app and there are no fault codes related to O2 sensor. In my mind, based on process of elimination, I am planning to change both pre and post cat O2 sensors to see if this solves my issue. DPF is regenerating as normal- haven’t seen any sign I can’t change in the mpg - this sooty exhaust is just bothering me a lot. I recall the exhaust used to stay absolutely clean but not anymore!
Any help would be appreciated
Thanks

You need ISTA. Bummerlink didn't show any codes at all on mine when it ran like crud, but ISTA had a fault memory code of 'Pre Cat O2 - too lean - partial throttle'.

Mine's on 70K and there's no soot at all on the tailpipes. The car does 400 miles a week though, so rarely does a forced regen.