I work on Fiats , if the code light does not turn off when you use the red key there are a couple of reasons . Your Engine control unit needs a code from your keys to stars the car it gets this from a code unit which reads it from your keys via an antenna.probable cause is a code unit whitch as a black box behind your interior fuse box cover.the only problem with this is once its fitted it cant be fitted to anything else so best of geting into an fiat delership.Hope u get sorted
Ev
March 2007