[s-cars] S6 starting problem - ECU fuse

[Mark Strangways]

If it is blowing with out having the ignition on, man I am thinking smoked 
ECU..

But they can be fixed.

Mark
----- Original Message ----- 
From: "Rich Beebe" <rich at beebecomm.com>
To: "James Murray (QA/EMC)" <james.murray at ericsson.com>; "Bill Mahoney" 
<wmahoney at disk.com>; "'Krasusky Paul (WQQ2PXK)'" <WQQ2PXK at ups.com>
Cc: "audi s-cars list" <s-car-list at audifans.com>
Sent: Thursday, May 19, 2005 7:18 PM
Subject: Re: [s-cars] S6 starting problem - ECU fuse


> actually, it's blowing the fuses without even starting the car,
> just by connecting the battery.
>
> i wonder if it would help to disconnect the POSs and attempt the
> fuse again? i've already checked the coil wires for a short and
> the ground - all seem fine. i'm gonna need more 5 amp fuses.
>
> i thought for sure, when i saw a blown ECU fuse, that it blew
> because of the jump-starting. now, when it blows a fuse every
> time the battery is hooked up, i can't believe it's something
> else - knowing it was running just the other day with nothing
> different. so strange.
>
> rich
>
> From: "James Murray (QA/EMC)" <james.murray at ericsson.com>
>
>> Rich, this helps...
>>
>> I'm assuming the fuse to the ECU blows only when you try to start the car 
>> and
>> not when the ignition is off and you reconnect the negative to the 
>> battery?
>>
>> This could be a failing POS (Power Output Stage) device... mine failed on 
>> me
>> last year out of the blue (but I later found out I had a coil that was 
>> also
>> failing, so I'm unsure if the failing coil caused the POS channel to 
>> degrade
>> and fail), anyway you could have a channel in your POS that has grounded 
>> and
>> failed... or even a coil that has failed.
>>
>> Try this test: unplug both POS, insert new fuse, try starting the car (of
>> course it won't start but you want to see if the fuse will blow), then 
>> plug in
>> one POS (repeat test), then plug in the other (repeat test). If the fuse 
>> blows
>> with either POS connected the it's likely the POS or a coil that has
>> grounded...
>>
>> Here's a good way to test the POS individually:
>> http://forums.audiworld.com/a4/msgs/1594531.phtml
>>
>> Cheers, /Jamu.
>>
>> -----Original Message-----
>> From: s-car-list-bounces at audifans.com
>> [mailto:s-car-list-bounces at audifans.com]
>> Sent: Thursday, May 19, 2005 4:12 PM
>> To: Bill Mahoney; 'Krasusky Paul (WQQ2PXK)'
>> Cc: audi s-cars list
>> Subject: [s-cars] S6 starting problem - ECU fuse
>>
>>
>> bill (and s-car list),
>>
>> i have checked the 5 amp ECU fuse and i finally found a blown fuse,
>> which i was hoping was a good sign. i unhooked the neg. battery
>> cable, inserted a new 5 amp fuse, but once i reconnect the neg.
>> terminal, it blows the fuse immediately. i'm unaware of anything
>> i might have done to cause this situation. most of the work was
>> routine (including CV boot, tie rod end, new stromung exhaust,
>> pads, rotors, hoses...), but i also fabbed up a CAI. the MAF is
>> hooked up fine and nothing else seems problematic. any thoughts
>> on what might be blowing the 5 amp ECU fuse? honestly, i'm at
>> a lose.
>>
>> thanks again for any help.
>>
>> rich
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>
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