Expert TD Keypad immobiliser problems

[ohms]

Hi all,

I have just purchased a 1998 Expert TD with the bosch pump and immobiliser keypad and I have been trying to change the keypad code without luck.

I have the manual so have been entering the new code in the way outlined in the book, but alas cannot get it to change.

When I enter the current code, both red and green lights illuminate and the immobiliser disarms and the engine starts, but if I try to change the code by pressing C after entering the original code it doesn't beep or recognise any of my further inputs.

I don't understand why both red and green lights are illuminating when I enter the code, and all seems to be working properly apart from that, and why it won't let me change the code.

ANy ideas??

Thanks:)

[spider]

They should not both be on, that indicates a fault typically a communication error.

If you wanted to, carefully examine the keypad wiring as it can break around the hinge (I think the expert's are hinged keypads) and examine the multiplugs on the fuel pump for corrosion etc.

Its only a slight fault by the sounds of it.

Its not at 1111 is it ? , as it may be in "service mode" I think the service mode code is read only but the customer code is changeable obviously. This is so you could set it to a different code and hand it over without revealing your code to the service dept etc, in reality no one ever used this.

[xmexclusive]

By 1998 the keypad/immobiliser routines had been changed to a variable garage code.
The variable garage code could be any 4 chosen digit code except 1111 or the current 4 digit code.
So the car now has two seperate owner selected 4 digit codes that will start the car.
The garage code is locked in by the owners code.
Serious problems can arise if a car so fitted is sold on without both variable codes being declared.
If you are given the correct owners code everything can be unravelled by following the instructions in the owners manual.
If you are only given the current garage code it cannot be changed because to do this you need the now lost owners code.
Next stage in this process comes with a battery disconnection which risks the immobiliser reverting to needing the lost owners code.

John

[spider]

Was not aware the garage code was changable actually, hmm. I do see the potential issue here too as you say. It should in theory survive in garage mode after battery disconnection as servicing is likely to involve that in some cases.

I do wonder what would happen (I don't have anything to test this with) if you yanked the CPH out when it was locked, if it would stay locked or otherwise. I know what happens if its unlocked and its 'tweaked' but I don't think I should post that.

[ohms]

So I got into the van yesterday morning and the keypad was completely dead...It wouldn't allow me to enter any codes at all.

I pulled the keypad out only to find that three of the wires to the unit had snapped. I managed to touch the wires back together so i could enter the code and start the engine...PHEW!!

I then completely disconnected the unit and the van has been starting without the need to input the code eversince, which is great, but...The van is booked in to have a cambelt next week, and the battery will inevitably be disconnected to carry out the work, so presumably I need to get the wires repaired and the keypad back in again before then.

SHould the code I have been using still work after the battery disconnect?? Not sure what you are saying about the 1998 onwards garage code.

Thanks chaps

[spider]

In theory it should be OK if the keypad is disconnected when its "unlocked" ie: green.

Can you not do a temporary repair job to the broken wiring ?

[wheeler]

Disconnecting the battery will not lock the imobiliser again, as long as the keypad can't talk to the CPH/injection pump module it will stay unlocked forever.

[xmexclusive]

Wheeler and Spider are right you should have no further problems unless you try to re-enable the keypad.
All the keypad immobiliser problems come with trying to start a dead vehicle.
Life is much easier with a running vehicle.
Once you have the vehicle running the ECU checks for changes in the keypad status.
If it sees the keypad being unplugged it records this information to isolate the immobiliser routines from future start-ups.
It will stay this way until it sees the keypad plugged back in while the engine is running.
Only then will it switch the immobiliser routines and keypad back in use.
Citroen/PSA alterered the keypad immobiliser system at least 5 times in just over 3 years.
There were also different versions for different markets.
Each change was intended to improve the immobiliser security to prevent car theft.
The car remote plip sets followed a similar development pattern over the same period.
All they actually achieved was confusion for customers and dealers.
Lots of well meaning but wrong advice got handed out.
It even got to the stage of cars supplied with out of date owners manuals.
Addendum pages if you were lucky.
Now the cars are well secondhand there is still a legacy from this mess.

John

[spider]

That's as I see it too. Just was OK in theory but in practise it caused a few too many issues unfortunately.

[Oldpug]

You can have the ECU altered to bypass the key pad altogether.I had this done many years ago on a 306 that I purchased as a non runner and no code known.(and no it was not a stolen car )