Peugeot 306 engine management light

Some weeks ago I put my 306 into the local dealer for a free diagnostic
check and update on the ECU. The results chowed a coil pack fault
however, I had only just replaced it, so the dealer reset the computer
and away I went happy and no managejment light!1 A couple of days ago
the light came on again and has stayed on? I bought a Gunsons fault
finder to try and see if I could get the fault code from the ECU but I
couldnt get the thing to work? Either I was NOT in the correct
diagnostic connector or the thing was faulty? Has anyone used the
Gunsons fault finder on a Peugeot and if so where does it get connected
too? Also, the dealer told me the Catalytic Converter was WORN, does
this show up on the diagnostic check or can it be seen physically that
it is worn?

 

I had the same experience with a Gunson's code reader. Check this page
to read the codes out:
http://www.peugeotdiesel.com/ECU_Faults.html

 

just take the car back

 

Yes, do that, but it's best to have some knowledge of the problem
beforehand because Peugeot dealers, esp IME, have a tendency to talk
complete cobblers, have little regard for fixing problems and when they
do attempt to, fail miserably.

 

.....and charge through the nose.