The 022D version of the Digifant ECU can and does store fault codes. If
you connect a switch and light to the wires like is shown in the 88-89
diagram you can display the codes. Yes I have done it.

The 1988 Vanagon owners manual shows the switch/light on the instrument
cluster and tells what it is for. The extra wiring was added to the
Digifant harness and to the dash harness. Some vans actually have the
cluster connector there but dangling with nothing to do.

This early OBD implementation was begun but never completed. The great
state of California was planning to require OBD for 1988 but delayed it
at the last minute and then allowed end of production life vehicles to
skip it. It is a very minimal fault code list, having to do with
emissions related stuff.

I'm pretty sure we have discussed this a few times here over the years.

Mark

Ken Wilford wrote:
> OK, so here is something that I might have seen before and just shrugged
> off but I have been confronted with it today again.  Page 97.123 in the
> Bentley Manual shows the ECU wiring diagram for an 88-89 Vanagon.  Pin
> 20 on the ECU is supposed to be going to something called a ECS-MAL Ind
> lt and switch.  I am thinking it is supposed to be some type of check
> engine light.  However if you go to page 97.205 you will see the diagram
> for a 1990 Vanagon.  In this diagram, the wiring is there but this
> mystery unit has been deleted.  I have spoken with ECU guru Darrell
> Boehler several times and he assures me that the Vanagon ECU never had
> the ability to store or generate fault codes of any kind.  I have also
> never seen any Vanagon come in here with any type of Check Engine light
> beside the OXY light which is a totally different thing than this.  So
> can anyone shed some light on what this part was supposed to be or why
> this is included in the wiring diagram of the earlier van but not the
> later?  It is just something strange that I found.
>
> --
> Thanks,
> Ken Wilford
> John 3:16
> www.vanagain.com
> Phone: 856-327-4936
> Fax: 856-327-2242
>