Sorry to resurrect such an old thread but I've had two instances of SID showing "theft protection failure - contact service" whilst driving. About a week prior to this, SID has shown and continues to show the message stating my key battery needs to be replaced. I've no issue with the alarm going off randomly or any other issues with the theft system. And so far I've only seen the message when driving with the key with the flat battery.
From fishing around for more info on WIS, I see that the siren unit wasn't used on and after chassis number 43013162 and the horn was used instead. Assuming that's the last 8 digits of my VIN, my chassis number starts 635***** so I presume I can rule out the "theft protection failure - contact service" message relating to the battery/ capacitor issue in the siren unit? But obviously could still relate to the tilt or glass break sensors.
I've just ordered a set of new batteries for both keys but could the message also be triggered by using a key with a duff battery?
Cheers