fob programming/Emergency start debug
If you're unable to program FOBs, don’t rush to buy a new immobilizer or send it out to be programmed - there may be low cost, DIY workaround.
The immobilizer relies on two signals for programming: KEY and IGN. Both come from the ignition/lock assembly, as shown. (In 1995 models, IGN also passes through the Airbag Control Unit.) During programming you enter the 4-digit PIN code by rotating the key ON and OFF following feedback from the immobilizer warning light. The KEY and IGN switches both need to be functioning properly or the procedure will fail.
FOB programming system in 1995 North American 993's:
FOB programming system in 1996-98 North American 993's:
During the programming procedure, the immobilizer expects the KEY switch to close after Step 2 and remain closed until the process is completed. If the switch opens, even briefly, the immobilizer will exit program mode. The tip-off that this is the problem is that the warning light deosn't flash after Step 3. If this happens, there are a few work-arounds you can try. The quick and dirty approach is to temporarily bypass the KEY switch by wiring 12V to it. This makes the immobilizer think the switch is working, allowing programming to continue. Getting to the switch can be difficult, but on North American 993 models, you can access the KEY signal at gong relay pin 85:
In North American 993 models, the gong relay is behind the fuel gauge. To access it, remove the gauge and unplug the tall relay. Wrap a piece of wire around terminal 85 and plug the relay back in. When you retry the programming procedure, connect 12V to this wire before you turn the key ON at the start of the process. If the warning lamp flashes after Step 3, finish the procedure, then remove the jumper. Do not leave the switch bypassed. (In RoW 993's you'll have to access the KEY signal at the switch).
If you have an IMMO BLOCK installed in the gong socket, you can attach the 12v bypass wire to this pin:
If you want to permanently fix the problem, first try replacing the low-cost KEY/BUZZER switch (P/N 911-613-125-00). Keep in mind, though, the issue may not be the switch itself but the internal mechanism that activates it. If that’s the case, you'll need to replace the entire assembly (P/N 964-347-917-01 or 00) - a more expensive part and a lot more work. Given that most owners rarely need to program fobs, the temporary bypass might be the way to go.
Less commonly, a faulty IGN signal will cause problems. In this case, the immobilizer enters programming mode ok (indicated by the immobilizer warning light flashing after Step 3), but it receives a corrupted PIN code due to chattering contacts. If this happens after repeated attempts, the ignition switch assembly needs to be replaced (part number 964-613-012-00).
