Can anyone tell me how to repair my 2001 honda civic lx sedan

The car cranks but won't turn over,
the immobilizer light does not come
on like it's supposed to. I took it up
to the honda dealership and they ran
a diagnostic and said everything was
fine. The only thing was that the
immobilizer wasn't responding to the
ecu. I also had them check fuel lines
and coils and everything seems fine.
Any ideas on how I can get this car
up and running again?