The check engine light and PO39 (a VCC torque converter) code on my 94 Eldo appear when I take a certain route leaving my house in the morning. I can drive for weeks other than that and no problem. In researching I learned that a revised calibration Prom was released to correct this problem. I did a test suggested by bbobynsky on the now defunct GM forums to see if the VCC is actually functioning and it is so now my question is has anyone here done this replacement? Is it hard to find where the prom is to be placed? I certainly don't want to cause more damage than I cure. It's really just an annoyance since the code can be easily erased but here in N.J. where they haven't found a new regulation they didn't like they are leaning toward turning down any car in their inspectin stations that have a check engine light or code on and making you take it to an "APPROVED SHOP" for repair. Please, any guidance would be great.