Help reading engine codes

[Phil Payne]

> As far as I am aware there are only two ways to get fault codes:
> 1 - using the fuse in the top of the fuel pump relay
> 2 - using the 2/3 connectors in the footwell.

No.  The earlier engines (those with separate idle and full load switches on
the throttle body - but not the ur-quattro) used the rev counter and check
engine light.

Take the cover off the switches, get the engine idling, and manually close
the full load switch while the idle switch is still closed.  Look at the rev
counter - if it says 7000 rpm even though the engine is only idling - that's
what you have.