I've had my car for just over 2 yrs, restoration project. I fitted a new battery at the time and she fired right up(diesel), I've been able to remove the battery a few times since and never had any issues with alarms going off, eka code, immobiliser issues, nowt, just reset windows, clock and sunroof.
My question is that the red led in the fob flashes once when the key is inserted in the ignition (that's normal I believe) so what does that one flash signify?
Would the car still start if the fob got wrecked? Just remote lock/unlock wouldn't work anymore, which it does fine. I don't have the eka code but I'm guessing I'll never need it? Because a previous owner had it all disabled?

You still have passive immobilisation enabled in the BeCM. If you unlock the car but don't start the car within 30 seconds, the immobiliser kicks in again. It needs an unlock code from the fob to reset it so there is a coil around the ignition switch that causes the fob to send an unlock code (exactly the same as you pressing the Unlock button) so it will start. If the coil fails, as they often do, it doesn't cause the fob to transmit so you get 'Engine Immobilised, Press remote of Enter Code' come up on the dash. As long as you unlock and then immediately start the car, it isn't needed. If passive immobilisation is turned off then the tie limit is removed and the fob will no longer flash as the car knows it isn't needed.

Just because EKA is disabled in the BeCM, doesn't mean it doesn't need it, just that it won't ask for it when it is needed. EKA should always be enabled but passive immobilisation should be disabled. In the menu on a Nanocom this is simply marked as Immobilisation so people disable it thinking they have disabled the immobiliser but they haven't, only passive immobilisation.

Thanks. I'll have to read that a few times to get my head around it.
Forgot to say, even my oe stereo doesn't need a code.

If it is a Clarion (pre-99), it will have been back to Clarion at some time in the past and they always remove the code. When first switched on after the power has been disconnected it will say NO CODE on the display and then it just works.

It's a 2001. Dhse.

I wd only contest your point about "EKA enabled" Richard... For a while i was worried that disabling the EKA would mean that the BECM would not still accept the EKA, bu then proved to mysalf that it does (by toggling the enabled/ disabled feature, and causing the engine disable to kick in... In that sense we are saying the same thing, but then what's the harm in disabling the EKA, rather than leaving it enabled ? I have my EKA disabled and haven't had to input the EKA for a long time - i had to do it twice in anger, on my previous P38 - once at a service station (which i suppose must have been electrical interference) and the other time when the battery went flat (left the lights on all night)

My understanding is that on a car that has an EKA programmed, it should be left Enabled so when needed it is asked for. On one that doesn't have it programmed, such as NAS cars, it should be disabled. As I understand it, if it is programmed but Disabled when it is needed the dash doesn't tell you, so rather than getting the 'Engine immobilise, Press Remote or Enter Code' message, you simply get an 'Engine Immobilised, Press Remote' message.

I think all NAS cars have it programmed to 1515

+1 on NAS cars having an EKA.
I don't know where this one got started, but I have looked at over
2 dozen cars with nano and have yet to find one without an EKA code.
It is true that most are 1515, but not all.
When I had Dr Scott from the dark side unlock mine, I recall him telling me that
I could change it if I wanted to as 90% of the Becms he worked on were 1515.....
If I recall, only in Australia is the EKA not used?? Please let me know if that is not true.

mine has an eka number and is Australian "97 gems "