Intermittent electrical problems
 

You may recall around this time last year I had the throttle position sensor replaced to fix an intermittent fault that resulted in the EPC and ABS lights coming on and the cat then driving with much reduced power.

I had a feeling at the time the the problem was linked to heavy rain, but after almost a year without any further trouble, I'd decided that was an unfounded suspicion.

Until a couple of weeks ago when, in very heavy and prolonged rain, it happened again.

Some fairly prolonged investigation revealed that the seal in the 'e box' was perished and, as the attached photos show, water was getting in. If you zoom in on the third photo, you can see water resting in the bottom of connector block 6 and the fourth photo shows some corrosion.

My belief now is that, in very heavy and prolonged rain, the water overwhelms the scuttle drains and, with a perished seal, can get into the 'e box'. And my guess is, if mine's perished, so is yours!

Unfortunately, Audi say that the cover and seal are on indefinite back order and the replacement I got from A8 Parts was worse than mine. So, time for the silicone sealant! I should get the car back today hopefully, and there's plenty of rain to test it!

Whilst the guys were investigating, I also got them to fix 'Botangs hole', so that'll be one less problem waiting!

That does look very damp indeedy. It needs to be bone dry in there....

I guess if it were just water, it would settle in the bottom of the chamber and cause little harm, but with the engine heat its probably a nice little sauna in there gently corroding all the components...

I suspect all will be well when you seal it up tight +++

Just heard that the new lid and seal will be delivered from Audi on Wednesday, so no need for the silicone sealant. Very pleased about that, as I'd much prefer to have the job done properly. :)

Thanks for the info Jim. Think I'll get mine checked.


I think mine's started letting water in there. I noticed the windows misting up again in the last few weeks. Front passenger side is getting a little damp and I know it ain't any of the drains 'coz I recently checked/cleared them all!

Definitely a good idea to check these boxes with all this heavy rain recently and probably still to come. I will be checking mine soon, may well be worth using silicon sealant once the box is dry.

think I may need to get stuck into Botang's hole too, passenger side wet but drains all clear:(

Hi Jim, many thanks for posting this experience.

Would you let us know part numbers for the lid/seal?
Will order immediately and change preventively.

I'd get some silica gel drying bags in there too. ;)

A useful trick is to weigh them first and again after a few days in situ.

I found that my big (1Kg) bags used for drying out the car interior (after blocked drains) would absorb up to 50gms each a day.
I just dried them on my boiler, again weighing regularly to check when they were dried out.

Should be able to get the part number when I pick the car up tomorrow, so I'll post it then.

Part number for lid and seal combined (apparently) is 4D2 937 128F.

A word of caution for removal and refitting: the screws that secure the lid, screw into captured brass threads that are fitted to the base of the 'e box'. A few of these had come loose, either because of corrosion and/or the plastic base becoming brittle with age. My garage used oversize bolts and nuts with locking washers to replace these (otherwise the whole box base would have to be replaced too).

So, over a week later, and a wallet relieved of a good part of its contents, and my beloved S8 is home again. :)