Hi John,
    I had the same question so I wired a circuit similar to the one in the bentley on a bench setup I have for testing ecus. When an
022d ecu started spitting out codes and I thought I had really found something. I soon learned differently.
     It appears vw/bosch  had plans to provide error codes/ logging with the 022d ecu. Actually part of the circuit is installed. If
you rig a switch / led per the bentley 97.123  you will find the 022d ecu will blink out codes.  The codes appear  to be the same as
some digifant 2 units that were used in the fox among others.  I have been unable to get any variations in the codes the ecu reads
out.  Regardless  what anomalies are put onto the system it always reads out the same codes.

Darrell

----- Original Message -----
From: "John Patton" <johnpatt@warwick.net>
To: <vanagon@gerry.vanagon.com>
Cc: <midwesty@midwest.net>
Sent: Saturday, June 23, 2001 9:30 PM
Subject: Digifant circuits

> Hi List,
>
> I've been meaning to post this for a while. I have an '86 and a '91 Vanagon-both
> Digifant controlled. The '91 uses two additional circuits; pins 20 & 23 that
> are not used on the '86. What does the '91 Digifant need to know that the '86
> does not??? These two circuits are shown in the Bentley.
>
> Regards,    John
>