Can I Disconnect The Immobiliser?

[xantiasufferer]

I have a 99 Turbo Diesel which, while mechanically A1 is suffering a lot of electrical/wiring problems.

A citroen garage wanted £1600 to re - wire the entire car, which is twice te value of the car!!!

 

Is it possible to by - pass the immobiliser so i can at least start the car?

The headlights, radio and all other electrics ae working, but the alarm, central locking and immobiliser are not - the car turns over but will not start!

 

I love my xantia to bits, but cant justify sending huge money on it, and would hate to be forcedto scrap a mechanically fantastic vehicle because of a few bad wires!!!

[Guest Colin Hunter]

Hello Fellow sufferer!

 

Seeing it's a '99 it will have the immobiliser in the form of a chip in the key rather than the numbered "Keypad" code set-up of the earlier cars. It is my understanding that this used to interface with a device on the fuel pump which did not allow the fuel to come on without the relevant code being put in. I imagine the later TDs (It's not an HDi is it?) would have a similar cut-off device on the pump. I have been told that if you try to tamper with it (ie remove it) then some kind of rod will fall down inside the pump and wreck it if it is turned over. This was intended as an anti tamper device. The pump has to go back to bosch to be re-built if the device is removed. I would imagine that the device could be fed power from some other source to fool it into thinking the immobiliser had been de-activated.

 

Perhaps your best bet would be to ask a bosch service centre if the device can be disabled and, if so, how to go about it. It may turn out to be quite simple to power it up from a 2nd circuit with a hidden switch and thereby retain some degree of security.

 

It may also be worthwhile consulting an independant auto electrician. I can't help thinking that there is some common denominator here linking the inoperative systems, but in the absence of a proper circuit diagram, I can't help any further.

 

Cheers. Hope this helps. :D

[xantiasufferer]

Hello Fellow sufferer!

 

Seeing it's a '99 it will have the immobiliser in the form of a chip in the key rather than the numbered "Keypad" code set-up of the earlier cars. It is my understanding that this used to interface with a device on the fuel pump which did not allow the fuel to come on without the relevant code being put in. I imagine the later TDs (It's not an HDi is it?) would have a similar cut-off device on the pump. I have been told that if you try to tamper with it (ie remove it) then some kind of rod will fall down inside the pump and wreck it if it is turned over. This was intended as an anti tamper device. The pump has to go back to bosch to be re-built if the device is removed. I would imagine that the device could be fed power from some other source to fool it into thinking the immobiliser had been de-activated.

 

Perhaps your best bet would be to ask a bosch service centre if the device can be disabled and, if so, how to go about it. It may turn out to be quite simple to power it up from a 2nd circuit with a hidden switch and thereby retain some degree of security.

 

It may also be worthwhile consulting an independant auto electrician. I can't help thinking that there is some common denominator here linking the inoperative systems, but in the absence of a proper circuit diagram, I can't help any further.

 

Cheers. Hope this helps. :D

[xantiasufferer]

Hello Fellow sufferer!

 

Seeing it's a '99 it will have the immobiliser in the form of a chip in the key rather than the numbered "Keypad" code set-up of the earlier cars. It is my understanding that this used to interface with a device on the fuel pump which did not allow the fuel to come on without the relevant code being put in. I imagine the later TDs (It's not an HDi is it?) would have a similar cut-off device on the pump. I have been told that if you try to tamper with it (ie remove it) then some kind of rod will fall down inside the pump and wreck it if it is turned over. This was intended as an anti tamper device. The pump has to go back to bosch to be re-built if the device is removed. I would imagine that the device could be fed power from some other source to fool it into thinking the immobiliser had been de-activated.

 

Perhaps your best bet would be to ask a bosch service centre if the device can be disabled and, if so, how to go about it. It may turn out to be quite simple to power it up from a 2nd circuit with a hidden switch and thereby retain some degree of security.

 

It may also be worthwhile consulting an independant auto electrician. I can't help thinking that there is some common denominator here linking the inoperative systems, but in the absence of a proper circuit diagram, I can't help any further.

 

Cheers. Hope this helps. :D

[xantiasufferer]

Hi,

Thanks for the advice Colin - you seem to be the man in the know!

Just to add some more details - it started today, but the electrics were all over the shop! Radio kept coming on and off - the instrument cluster would stop working, then when i used the indicators the instrument needles would flicker up and down a few times then start working, only to go off again a little further down the road!

I am starting to believe this is some kind of central wiring problem rather than the immobiliser!!

 

Hello Fellow sufferer!

 

Seeing it's a '99 it will have the immobiliser in the form of a chip in the key rather than the numbered "Keypad" code set-up of the earlier cars. It is my understanding that this used to interface with a device on the fuel pump which did not allow the fuel to come on without the relevant code being put in. I imagine the later TDs (It's not an HDi is it?) would have a similar cut-off device on the pump. I have been told that if you try to tamper with it (ie remove it) then some kind of rod will fall down inside the pump and wreck it if it is turned over. This was intended as an anti tamper device. The pump has to go back to bosch to be re-built if the device is removed. I would imagine that the device could be fed power from some other source to fool it into thinking the immobiliser had been de-activated.

 

Perhaps your best bet would be to ask a bosch service centre if the device can be disabled and, if so, how to go about it. It may turn out to be quite simple to power it up from a 2nd circuit with a hidden switch and thereby retain some degree of security.

 

It may also be worthwhile consulting an independant auto electrician. I can't help thinking that there is some common denominator here linking the inoperative systems, but in the absence of a proper circuit diagram, I can't help any further.

 

Cheers. Hope this helps. :D

[Guest Colin Hunter]

Hi Again. Citroen, in common with other manufacturers, use "Earth equipotential points" or, to put it more simply, common earth posts. That is, the earth or return wires from many services, find a common way to ground through one of these points or posts.

 

The problems start when the common earth point isn't earthing properly, and the current from each service that uses the common earth, can't find it's way back to the battery via that path and has to find another way, usually via some other, seemingly un-related, piece of equipment which then appears to be going NUTS! (Hope you follow that!)

 

I have heard from, and replied to, another person with similar problems within these forums. I suggested a common earth point then but unfortunately I cannot remember what the outcome was, or even if the person followed it up. I have no personal experience of this with my Citroens, they have been electrically OK (SO FAR) but have had similar things happen on other vehicles. Once you find the dodgy earth point and make it good all the problems seem to cease at the same time.

 

My first point of call would be under the dash. Take off the panels underneath in the area of the fuse box and see if you see something with a lot of wires coming to it which seems to be connected to the bodywork. There will be more than one so look well. They will be your earth points. If there is any dirt or corrosion where they are connected, clean it up and remake the joint with some "No Crode" battery terminal paste or similar to prevent further problems.

 

If anybody else has personal experience of where to find the earth points, NOW is the time to speak up!

 

Cheers. Hope this helps :D