Fusebox internals - map/diagram

[John Cody Forbes]

A logic probe is like a test light, but with fast reacting LEDs and protection circuitry to make it safe for testing low amperage ECU circuits. I love the one I got from Matco, though I can't find it on their website. It's got a very long cord with two leads (power and ground, which all logic probes have). It's got a red LED to signify positive voltage and a green one for ground.

 I can get the part number off mine in a bit, I'm getting ready to head to the shop now that the F1 race is over.

-Cody (mobile)

On Sep 26, 2010, at 9:32 AM, "Ben Swann" <benswann at verizon.net> wrote:

> Cody,
> 
> What do you use for a logic probe?  
> 
> I don't seem to have great luck with my multi-meter, but maybe I'm not doing it right. 
> 
> Ben
> 
> -----Original Message-----
> From: John Cody Forbes [mailto:cody at 5000tq.com] 
> Sent: Sunday, September 26, 2010 7:54 AM
> To: audi at humanspeakers.com
> Cc: Ben Swann; quattro at audifans.com; 200q20V mailing list
> Subject: Re: Fusebox internals - map/diagram
> 
> Absolutely correct. It's still worthwhile. 5 bad coils are pretty unlikely, so if you've
> got NOTHING this is at least as good as checking a plug wire with an inductive meter or
> timing light. 
> 
> POS = Power Output Stage. The early VAG coil on plug cars have them. It's a small pack
> of transistors so the current flow to power the coils doesn't flow through the ECU. An
> AAN has two of them, they have three coil circuits each.
> 
> -Cody (mobile)
> 
> On Sep 25, 2010, at 11:58 PM, Huw Powell <audi at humanspeakers.com> wrote:
> 
>> That tests the ECU and whatever POSs are.
>> 
>> It doesn't actually "check for spark", though.  Bad coil, bad plug, drowned spark, you
> wouldn't find them, right?
>> 
>>> Just use a logic probe to back probe the coil connector for checking 
>>> for spark. If the signal is getting to the coil then the ECU is doing 
>>> it job as well as the POS's.
>> 
>> 
>> --
>> Huw Powell
>> 
>> http://www.humanspeakers.com/audi
>> 
>> http://www.humanthoughts.org/
>