2001 S8 Lambda Sensor info please?

[GlynH]

Hi there,

Just getting ready to spend some money on my S8 and was wondering if some kind soul could advise on the following error please?

I am guessing this points to both pre-cat Lambda probes but want to be sure.

It would also be a huge help if I knew the part numbers of the correct Lambdas...wish I had access to ETKA, ELSAWin etc. etc.

Can anyone help with that also please?

Fault codes below;

----------snip----------
Thursday,16,September,2010,08:03:42:23606
VCDS Version: Release 10.6.0
Data version: 20100630

Address 01: Engine Labels: 4D0-907-560-AVP.lbl
Control Module Part Number: 4D0 907 559 C
Component and/or Version: 4.2L V8/5V G 0003
Software Coding: 10753
Work Shop Code: WSC 02314
Additional Info: WAUZZZ4DZ1N013077 AUZ7Z0Y1749867
VCID: 2E574731C07C
2 Faults Found:

17521 - Oxygen (Lambda) Sensor; B1 S1: Internal Resistance too High
P1113 - 35-10 - - - Intermittent
17539 - Oxygen (Lambda) Sensor; B2 S1: Internal Resistance too High
P1131 - 35-10 - - - Intermittent

Readiness: 0000 0000

Thanks & kind regards,
-=Glyn=-

[ADU UR quattro]

I believe you need both front lambdas, on the downpipes, I'm sure some one with more knowledge will step up soon and correct me.I had the em light on my car, but only needed 1 sensor.its been much better on fuel economy since the new sensor was fitted.

[GlynH]

Thanks for the reply. My MPG is currently on 22.something-or-other but then again it is mostly motorway and I have not been pushing it much...content to sit at 70-80 for most of the time as is overdue a service & cambelt...wouldn't want that to let go! :(

Mine does seem to have a lumpy tickover...not sure if that is because of the Lambda probes or not?

I also get intermittent emission warnings up in the cluster but can clear it with VCDS...it just comes back again a day or two later.

If any kind soul can help with part numbers for these it really would be much appreciated.

Thanks & kind regards,
-=Glyn=-

[Conan_the_Librarian]

Front = b 007906265 x 2
Rear = b 0777906265H x 2

[GlynH]

Sorry Mike...I must have missed this one... :o

Not wishing to draw your meticuluous library records into disrepute but I have been doing some looking myself...looks like there might be a typo above or my own research could be wrong? ;)

Probe 077906265J
Probe 077906265H

It would appear that the H is nearly a tenner cheaper than the J for some reason?

I am guessing when you refer to front this is pre-cat (before) and rear is post-cat (after)?

I might submit my list so far to a dealer and ask them to check part numbers are correct and see if they might offer a discount on a job lot?

Thanks & kind regards,
-=Glyn=-

[Conan_the_Librarian]

sorry Glyn! :(

Fronts are 077906265J

http://forum.a8parts.co.uk/attachment.php?attachmentid=1419&stc=1&d=1287129369

[GlynH]

For Gods sake Mike...there is really no need to apologise! :ROFL:

As always a mine of information...much appreciated.

Kind regards,
-=Glyn=-

[Cornershop]

folks!

Can anyone recommend an alternative source for the front lambda sensors as both my pre-cat are flagging in vcds, according to my indie.

Audi want 160+vat each (seems everything I needto change is 160 + vat :rolleyes: )

I believe Bosch 0258006159 are equivalent - anyone tried these at circa half the price?

Cheers

[Goran]

I think you should be ok, its manufactured by Bosch so should be identical?
Here is a picture of my old front lambda that came out of my previous facelift S8, this is the Audi original one, as you can see (sorry a bit blurry) it has the same Bosch number plus Audi stamp their own number on it.

Here is a cheap one on Amazon.

http://www.amazon.co.uk/Bosch-0258006159-Oxygen-Sensor/dp/B0068MXWRW

http://forum.a8parts.co.uk/attachment.php?attachmentid=10342&stc=1&d=1426326018

[Cornershop]

Thanks Goran, I had that bookmarked. Glad to hear there are cheaper sources.

Apparently both my pre cat sensors are stuck solid and will need the down pipe to be dropped as well as the Kombi valve removed

Not a cheap piece of work all in all

[HPsauce]

My post-cat lambda was totally stuck in when they replaced my nearside cat the other day.
They removed it eventually on the bench (to send the old cat back) but the thread was too damaged to reuse.
Shame as it was otherwise still perfectly ok. :(

New one cost £67.99 plus VAT, I think from TPS. :-(
That wouldn't be a cheap one, my garage only use OEM (or main manufacturer equivalent) so presumably a Bosch one.

[brasiliangringo]

They are all pretty much the same, i have cut and crimped heads from different number BOSCH sensors provided they have the same number of wires ie 5 wires are wideband narrow 3. Never solder as this prevents atmospheric air from getting down into the sensor head needed by the sensor to calc the diff between normal o2 in atmosphere and that in exhaust gases. I have tried it and you get a code with solder (!) which seals off the fresh air supply from traveling down between the insulation and wire - hard as it is to believe from looking at the wires!

[brasiliangringo]

Get the Bosch number and search it out like that - diff countries also have different numbers to complicate it but there are some fairly cheap Bosch vendors if you sniff out the correct Bosch PN - whether it works for sourcing one for the S8 i cant say but worth a go..

[brasiliangringo]

folks!

Can anyone recommend an alternative source for the front lambda sensors as both my pre-cat are flagging in vcds, according to my indie.

Audi want 160+vat each (seems everything I needto change is 160 + vat :rolleyes: )

I believe Bosch 0258006159 are equivalent - anyone tried these at circa half the price?

Cheers

Yes with different cars no problem, the sensor heads are all generally the same with exception of narrow and wide band sensors - the latter can measure fuel trims at WOT.

[HPsauce]

My post-cat lambda was a Bosch 0258010073. About £70 on Amazon.
I would expect the pre-cat to be similar/identical.

[ainarssems]

I have in the past (not on 8) also use different Bosch lambda sensor from different car by just changing the plug from original. I did solder it and it still worked without any issues but it was not easy to solder as the wires were stainless steel instead of copper. Most of them are the same with difference being cable length and plug but there are some odd ones with different size.

As far as narrowband/wideband go most of production cars are narrowband with exception of some exotic cars and fuel stratified engines which run lean. Difference between 3(2) wire vs 5(4) wire is that extra 2 wires are used for heating element to bring it up to temp sooner and pretty much all these days are heated versions except for some older cars. Most narrowband come with 4 wires these days, wideband will normally have 5 or 6 wires.

[brasiliangringo]

Plenty of cars have wide band - the Mk1 TT / S3 BAM does and that was made in 2000/2001 not new or exotic really. (All the 2.0 TFSIs have wide band, common as muck)

Soldering is considered a no no for wiring up o2 sensors and that's the manufacturers advice given how they function, not mine. You may ofc get lucky as you did if there is a slight gap with solder to allow air travel.

[Goran]

Sorry to hear they are both stuck. I guess its best not to second-guess the mechanic, I wonder if some anti-seize product might dislodge them.
My mechanic removed both of mine from above, no exhaust dismantling needed, at 80k, but maybe I was lucky that they weren't stuck.
His trick is to use a crow's foot wrench and long 1/4" or 3/8" extension and remove only the SAI combi valves (polished steel mushroom shaped things on back of the engine block).
It was really quick doing it this way.

[brasiliangringo]

He did the pre cats on an S8 without removing the pipes ?

[brasiliangringo]

Impressive work on his part if it was. I never gave it any thought but obv is possible if they are not too stuck - worth trying 1st then, but i think you were lucky as they often need a hex deep o2 socket and impact wrench to shift.

[Goran]

He did the pre cats on an S8 without removing the pipes ?

Yup, both from above, I watched him do it, they are accessible, and yes, the 'crows foot' wrench is a diesel/O2 deep socket that can be bought on ebay.
I suspect someone with long arms and with guidance from above could even access them from below without removing the downpipes. Is there enough room to swing a hammer though, to dislodge them?

This is what you need, maybe not this exact one, together with a long extension bar.

http://www.ebay.co.uk/itm/O2-Oxygen-Sensor-Offset-Socket-Vacuum-Switch-7-8-Inch-/351327741927?pt=LH_DefaultDomain_0&hash=item51ccc3e7e7

[brasiliangringo]

Not that I recall and those crows foot vgood if they release with a bar. You wld need a direct one not offset for Impact wrench but obv ideal for the application your mech used.

[Goran]

The offset one gave more leverage for undoing the old lambdas at least I think this is the one he used, you cant use it for doing it back up to the correct torque unless you do some maths and adjust for the lever action of the crows foot.

Edit - although thinking about it, maybe a direct one with a longer wrench on the end of the extension is better.

[brasiliangringo]

Its for access they offset them, the leverage is compromised given the offset join - torque is lost (or not fully transferred to the target) given the 'play' in the connection at the offset joint.

[Cornershop]

Sourced the parts from eBay - user autokrake-autoteil offering them for circa £60 delivered.

Genuine Bosch items, sealed boxes with Bosch holograms etc. good deal I thought.

[brasiliangringo]

yep sounds alright to me, cheaper than buying from Audi !