immobiliser will not deactivate following flat battery

[RichardH]

Hi, I have an 1994 S2 which has been off the road for 2 weeks while sorting cooling fans and electrical circulation pump. Came to restart it and the battery was flat, so disconnected it and recharged on a mains charger back up to full power. Now reconnected, the alarm remote is not locking or deactivating the immobiliser. If I put the key in the ignition and turn, the indicators flash 35 times, if that means anything, but that is all. I have tried powering down and reconnecting (well it works on the computer) but no change. Any help would be appreciated.

[Rambo]

I have the same problem too and haven't found a solution yet so interested in any replies.

Mine happened after a grid outage and I forgot to check to see whether the connected CTEK was still working (the outage had tripped the safety cutout on the extension lead !)

[Saltire]

Well, that’s a new one on me - and I thought I knew pretty much all the wrinkles of the S2 alarm system

The S2 came from the factory with an alarm fob integral in the main key, and a separate rectangular fob, both of which can be used to arm/disarm. Do you have both? And does neither of them operate the alarm / central locking?

I suspect (although I’ve no hard evidence) that the alarm control unit has ‘forgotten’ the unique code number from the fob. There is a way of reprogramming this IF you know the original code number - but it doesn’t always work. Sad to say, I fear your only solution may be to strip out the OEM alarm and replace it - that’s what I had to do.

I have a write-up on how to do this, but I don’t publish it on the open forum for obvious reasons. (Pinky also has a copy in case I go under a bus ). If you email me at my forum address, I’ll be happy to send it across, but be warned: replacement is quite a major undertaking.

[RichardH]

First up thanks for replying. I have the original rectangular fob with the grey and red buttons, plus a separate round fob which doesn't carry the Lotus logo so may have been a replacement at some point. Although the transmission lights come on, neither activates the central locking or immobiliser. When I bought the car, however, the keys came in a small plastic bag on which numbers are written. One set is letters and numbers but the other a 10 number sequence, could this be the 'lost' alarm code? Prior to this episode the alarm had been faultless, but after 30yrs I suppose these things happen.

[RichardH]

Having visited my local Lotus specialist Allon White Sportscars(who are superb) to request a pick up to sort this problem, they spent some time just talking it through. Their assessment was that it was to do with the battery (new in May) as any voltage drop can cause anarchy with the Elans electrics, and suggested initally charging for an extended period to ensure the battery was fully charged. As going away, left the car on charge for five days which on return showed the battery fully charged, much as before but presumably now up to max. Then tried the key fob, and unbelievably the car unlocked and was able to be started. The problem would appear to be that anything below 12v allows potential malfunction, which is what they suggested, and thankfully their assistance saved me a large bill.

[Saltire]

Thanks for the update, Richard; you learn something new every day

[Simon_P]

Do the alarms have a built in battery so that it still sounds after the potential Thief removes battery powered?
I have found in the past that this needs enough time and volts to recharge. Also the old batteries in them can leak and cause havoc.