Doug
The sensible approach is to take it at literal face value.
My guess or bet if you like is it is connected to an auto-arming immobiliser. I suspect if it is lit, this is an indication that the engine is immobilised and you need to plip the button or whatever to get the ignition to start the engine.
Probably a new wiring feature with the later wiring.
Just to elucidate, OBD 11 according to Phil I think, is only fitted to US cars because US legislation required it at that time.
The rest of the world had different OBD diagnostics which were not mapped to the OBD 11 protocols. Possibly the rest of the world got a variant of the Japanese protocols, or a protocol that mapped into upcoming EU legislation, I don't know.
In any event they are different.
This may be why this particular button is wired up as a status indicator.
Just my guess.
Joe
__________________
Black Betty [Bam a Lam!] '93 UK spec, still languishing
Betty
Jersey Girl Silver '92 UK [Channel Isles] 40K
Jersey Girl @ Mersea
Candy Purple Honda Blackbird
Plum Dangerous
White X2 RVR Mitsubishi 1800GDI.
Vantastic
40,000 miles Jersey Girl