The Outcome (Part 2) of "Audi just shuts off no warning while driving and won't restart"

[Marc Boucher]

I'll be definitely going at it now with a volt-ohm meter to try and get it 
back to match the schematics.

If you had to guess, were they trying to establish ground from the hall 
sender, and they meant to connect the "green-white" cable depicted as "0" on 
the schematics to the engine block, rather than the brown-white labelled "-" 
?

The schematic shows that the IGN booster has a brown-white cable which is 
connected directly to ground.  If they suspected a ground problem involving 
the IGN booster, why not ground the IGN booster, not the hall sender?

I realize that this is beside the point, since the main point is to get it 
back to match the schematics.  But I thought it would be useful to try and 
understand what they did and why they did it, since it DID solve the problem 
of the car not running.

Thanks again,
MC

--------------------------------------------------
From: "Huw Powell" <audi at humanspeakers.com>
Sent: Wednesday, August 17, 2011 10:34 PM
To: "Marc Boucher" <mboucher70 at hotmail.com>
Cc: <quattro at audifans.com>
Subject: Re: The Outcome (Part 2) of "Audi just shuts off no warning while 
driving and won't restart"


>>
>> Looked around to see what exactly they did to solve the "ECU ground"
>> problem. *It appears that they cut the brown and white wire wire coming
>> from the Hall Generator, and bolted it to the engine block in order to
>> act as a ground. The schematics show that wire should go directly to pin
>> 10 on the ICU.*
>
> Nice work.  Striped brown wires are *switched* grounds.
>
>> **
>> Their invoice says that they "Check wiring from ignition distributor
>> coil and ignition ECU, Determine ground signal wire from ECU not
>> functioning, Repair ground wire". According to the schematics, red-black
>> wire is "+", the Brown-White is "-" and the "green-white" is "0". Does
>> that make sense, to connect the brown-white wire to the engine block for
>> ground? If not, could that have defeated the ISV ?
>> MC
>
> If it made sense, it would have come that way from the factory.  It might 
> be time to dig out or buy a VOM and do some checks yourself.
>