355 immobilizer removal
How to remove a F355 immobilizer box
Move drivers seat to full forward position and lean forward. Then shut off power to car at disconnect switch in front. Remove 2 bottom screws of panel behind seat on engine firewall, press in gently and push up to release panel.
Remove 3, 8mm nuts holding immobilizer metal case and wiring from firewall (note blue wire is antenna to immobilizer).
Metal case can now be rotated freely to drill out 8 pop rivet heads holding metal case halves together, with appropriate drill bit of 3/16"-1/4". Do not drill deeper than maybe 1/4"! I've had someone drill 2" into the immobilizer box and I had to repair the board inside.
Separate case halves, remove immobilizer, disconnect blue wire/antenna connector and 2 other connectors at bottom of unit. *Note wiring routing for re-install.
Replacing Rivets
Using a hand pop rivet gun, using 1/8" diameter rivets by 1/4" long, rivet metal case back together with immobilizer connected inside and proper wiring/antenna routing exiting metal case.
After case halves are riveted back together, reverse install making sure connections are seated firm, power up car at switch, wait 2-5 minutes for circuitry to stabilize. Proceed to normal start up of car.