I have two ODB readers one is my SCT tuner, the other is a generic Bluetooth transmitter going to my Torque app on my cell, that one tells me if the DTC is current or a History (past) code.
That is why I ask. Usually if you clear them you just need to see if they come back. If it is a current on going issue yeah you should see it pop up right away.
Right now I have one History code for P1639 which is a VID DTC. I had my ECU reflashed by the Dealer to a different strategy for the new gears. So I expected to see this. (also happens if you get a new computer from the dealer and they do not transfer the VID info from the old unit).
Its too bad the SCT does not give a little more detail than it does on the codes like the torque app does =)
Also remember every time you flash your computer it resets the on board diagnostic tests (DTC P1000). If you are doing any warranty work and you flash back to stock before dropping it off at the dealer make sure you drive it plenty before (80-100+) miles so it can finish the tests and clear that code before you go in for service. And do NOT clear the codes manually if you see P1000 as it will reset the test and it will start over from scratch (another 80-100 miles of driving).
Same thing goes for pulling the fuse (#47) on the ecu.
-D
__________________ 11' Mustang Convertible | 3.7L | 3.55 Ford Racing gears w/SVT cover | Vibrant 1792 Resonators | Dynomax cat backs | AT | JLT cai | MPT 93 race tuned | GT bumper | Saleen S281 grille | CDC Chin spoiler | Roush Rocker splitters | GT500 Rear fascia | CDC Lightbar | Raxiom smoked head\taillights | Blacked out side markers | embroidered floor mats | Custom leather seats Black on tangerine | Custom two tone paint RM jet black on House of Kolor Kandy Base Coat Tangerine, Glasurit Clear. | 
