Yes, the 88 and newer Vanagon ECU (022D)stores trouble codes. If you
hook up the extra wires and light to it you can display the trouble
codes. If you look in the 1988 Owners Manual the instrument cluster
section shows the ECS Malfunction light and switch on the dash cluster
and it tells what they are for. I have never seen or heard of an 88 that
actually had these but clearly it was intended at some point.

Mark

neil n wrote:
> Very interesting.
>
> I see ECU 23 shown in the later MY diagrams.
>
> Was this OBD capability planned part and parcel with the
> "programmable" (my term) ECU's?
>
> Neil.
>
> On Mon, Mar 11, 2013 at 9:44 PM, mark drillock <mdrillock@cox.net> wrote:
>
>> The 5 pin ECU power relay has nothing to do with the fan or AC, contrary
>> to various parts venders listings. The extra relay pin has to do with
>> the OBDI capability that VW was working to implement into the Vanagon to
>> comply with pending emissions regs. FI harnesses that are set up for the
>> 5 pin relay have extra ECU wiring pins and the 5th relay pin connects to
>> the ECU on one of these.
>
>
>
>