For Sale Rover Immobilisers - No "Passive Arm" - Sale or Swap

[revilla]

Standard Rover / Lucas 5AS immobilisers. 3 available. Suits standard K Series.

These came in two flavours (I think it's just a matter of programming, but I can't find a suitable programmer to play with them!). Some were set arm the immobiliser a few minutes after switching off the ignition (so called "passive arm"), some weren't (in a Rover, they all arm the immobilser after a few seconds if you switch off the ignition and then open and close the driver's door, but in a Caterham there are no door switches).

Some people (like me) prefer the added security of the passive arming immobiliser. Some people would rather not have the hassle of an immobiliser at all and wish they could switch it off and forget it. Well, if you're one of those people ... these are perfect for you!

I have a number of spare immobilisers, some of which are set to passive arm, some of which are not. So I'm selling the ones which are not.

These will immobilise the engine if you press the "lock" button on the key fob, but if you turn them off with the "unlock" button and leave them, they should stay off. They won't turn on after a period of time, they won't turn on if you disconnect the battery etc. If you want to, you can just turn them off and forget them. Or you can set them as required.

You will need the immobiliser coding to your key fobs and your ECU coding to the immobiliser but I've got a key programming setup and I can do this for nothing if you want one of them.

£10 + P&P each.

Alternatively, if anyone has a passively armed immobiliser and wants a straight swap, that would suit me fine. Again, I'll code them up as required.

[MikeMolloy]

Passive is Bit 2 of EEOPTSA. Can you bit twiddle that with Testbook (or whatever your software is)?

[revilla]

Mike,

Thanks for that - unfortunately I don't have Testbook (would be nice!) or any other sensible software. To be honest the only way I've got to change anything is bit twiddling directly in the EEPROM on the microcontroller.

Any info you have on the 5AS would be appreciated (either on here or by PM). At the moment I'm having to hack it from first principles. I've spent the morning staring at the signal from the 5AS with an oscilloscope trying to decipher it. I think I've got it ... 16 bit data word, padded with 0s after each bit, then NRZ-Space line encoded, and a 4-bit header 0111 which when you decode the NRZ-Space contains a 1-padding bit rather than a 0 to mark the start of the sequence ... am I on the right lines here?

Thanks,

Andrew

[MikeMolloy]

Mmm, it's 25 years since I worked on the 5AS, but the MEMS code is 2 bytes, transmitted at 125 HZ.

All codes are valid apart from 0x0000, 0xFFFF and 0xF0F0.

[revilla]

Yes that fits with what I'm seeing. I'm seeing bit times of 4ms which would be 250 bits per second, but with a padding bit after every payload bit that makes 125 payload bits per second. Thanks for the heads up on the illegal codes. I'll carry on hacking