Immobiliser Help !

Hello All,

My first post here,

ive just got myself my first 4x4, a 300TDi Disco,

only had it a week and i love it,

But, from time to time my immobiliser takes for ever to turn off, ill get in the thing, put the key in, glow plug light goes off and the red light will still be flashing,

this is on the master key too? or atleast the dongle is red,

the other key with the black dongle on is the same too i believe, the immobiliser wont work at all with that one i believe

is there an easy fix to this?



Thanks




Mike

hello m8 ive got a 300tdi and it dose the same thing jus keep taking the key out and putting it bk in i dont think u can fix it,,,,,,,,,,,,,i mite be wrong about the fix part

The immobilsor should work by radio signal (I think). There is a transmitter in the key fob and a receiver around the ignition barrel.

So the problem is that sometimes a signal is either not sent or not received. Do both fobs work the central locking ok? If so, then the fob battery should be ok.

Next, I'd check he wiring connectors to the receiver. Intermittent faults could be loose connections.

What state are the fuses in? Could be a bad connection there too.

Finally, if all else fails, then it may be time to look into the dreaded 'spider'. I'm no expert but if your model has one, it could be that at fault. A bit time consuming to get to but easy enough to fix or bypass if required.

Of course it could be something more complex such as the ECU not recognising the code but I have no knowledge or experience about that.

Hope this gives some pointers to help out.

As far as I can remember, you can keylock the TDi without setting the alarm. Might that help? TD5 is another matter: the system seems to be one of the worst points about the car. So far I've had two dodgy fobs (cost a fortune to replace), and one occasion when the alarm/imobiliser just refusd to switch off. Panicked, went away to calm down, came back an hour later and it worked fine. I have visions of this happening somewhere up a mountain in Eastern Europe and having to get rescued by a Dacia or worse.

Hi There,

Thanks for the replies,

Both the keyfobs unlock and lock the car,

But one of them has a black plastic thing hanging off it and the other one is red, the black one will not switch off the Immobiliser at all,

The red one works alot of the time, but not always, then when i pull the keys out it the light stops flashing

it does work in the end after prob 20-30 seconds, sometimes works if i shake the keys around too

is the Immobiliser part actually inside the key fob then?

the man i bought it from kept saying the Immobiliser was done on these little plastic things hagging off the key

Hello again.

On my 300TDi, there is a receiver around the ignition barrel once you take the cowling off. The fob needs to be close to this to deactivate the immobilisor.

I think (don't know for sure) that the fob has a chip in it that is read by the ring around the ignition barrel. So it sounds to me like your 'receiver' isn't seeing the chip.

This could either be a simple (dodgy connection somewhere) problem or a more complex ECU problem.

Try the wiring connections including fuses first.

Before you go and spend £50 getting yourself a spider, check out your discovery's earth wire.

My immobilser kept kicking in and dying on me all the time and the alarm went off all the time aswell. Look right behind the battery there is a 10mm nut holding on 3 connections, get a bit of wet and dry paper on the threads the base and all the connecters and bang it back together. Never had a problem since it even fixed the dodgy lights I had.

Check yours out and I bet its well rusty. Hope this helps cos I was about to sell the thing cos it kept leaving me stranded all over the country. : )

Moyes87

You must have a early 300 with a single button fob, the immobiliser is an extra protection systen added by a LR dealer for insurance reasons as the early 300s only have engine isolator, not accepted by some insurance compainies as an immobiliser is.
Later 300's have passive immobilision where the two button fob only has to be near the ignition switch to remobilise the engine.
Also even if you lock your disco with a key the alarm is still set thats standard unless your system has been modified, then who knows.
You could speak to the previous owner regarding the correct function of the fobs.