Immobiliser Replacement

There are two types of TVR out there; those that have had the original immobiliser replaced already, and those that haven’t – yet.
We’re not talking “dodgy TVR electrics” here. These immobilisers were warrantied for 7 years- these cars are 20+ years old now. So actually, they’ve done quite well!

Warning signs your Immobiliser is faulty

The general consensus is, these original units don’t just suddenly die completely; they die a slow death, and as such there are warning signs. The symptoms mine was failing, was that the starter was not engaging. I would hear the fuel pump prime, but on pressing the start button.. nothing would happen. It would take a few attempts, and then it would suddenly come back to life. It only seemed to happen on a cold-start.
Hearing the fuel pump prime each time led me to misdiagnose this as a starter motor problem. I now have a new starter motor, plus a perfectly working spare. ?
So how do you know if it’s the immobiliser at fault?- it’s not easy. There are 3 separate systems controlled- ignition, fuel pump and starter motor. The starter motor is usually the first to go due to it having the highest load through it.

My advice: at the slightest sign of trouble, get it replaced- it’s just a matter of time anyway.

21st Century Immobiliser and Alarm

There aren’t that many people who specialise in replacing these immobilisers in TVRs, but I was lucky enough to catch Carl Baker while he was in the UK.
So what does the new one do?

  • It has a 50% reduction in parasitic battery drain – in other words you can go on holiday for 2 weeks, and not come back to a flat battery.
  • It has a proximity sensor, so that when you are in range of the car, the car is not immobilised- meaning you just press the start button- no faffing around disarming or rushing to beat the time limit before it arms again.
    It’s smart too- the proximity sensor will go to sleep if it hasn’t moved for a while- so if your keys resting place in the house happen to be in range of the car, all is good.
  • There is a button on the remote to open the boot.

It’s like a modern car!
old alarm immobilisernew alarm immobiliser
Old on the left, new on the right. (Serial numbers etc obfuscated)
Side topic: what do you make of the scribble on the fibreglass panel?
These cave drawings & scribbles are quite common. Builders from the factory often signed their name, or sometimes left a cave-drawing. Someones initial maybe? or were they interrupted while drawing something else? ?

2 thoughts on “Immobiliser Replacement

  1. Peter Manewell

    Interesting report about immobiliser faults. My cerbera has similar symptoms which started recently. Today I could not open to door. My thinking was that the battery had failed but may be its the immobiliser. I would appreciate some advice on where to go to for a replacement.

    1. admin Post author

      The simplest/quickest possible solution is to replace the battery. If it hasn’t been replaced in a while, you can do no harm by replacing it.

      If that doesn’t solve it, maybe the door module in the boot is fried- they’re not easy to find a replacement- maybe a fellow local Cerbera owner will let you plug theirs in to see if it solves the problem.

      Lastly, yes maybe immobiliser- for this there’s little a DIY-er can do to work around that, but there are specialists out there than help you temporarily bypass it.

      If you need any contacts, let me know.
      Good luck!

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