Technical Central locking and key wil not work using button

[billy bunter]

I have found lots of very useful info from this site. but I am finding this problem a little perplexing and am hoping someone can help.

I bought a 1999 MK1 Sporting a few months back and have been slowly working my way through some common problems with it. eg Noisy wiper motor due to the scuttle drains being blocked.

I have a red key and one blue key with switch. Both work the car correctly however the central locking switch has never worked. I always have locked the s2 doors using the blue key in the lock. The blue key looks like this and has the part number 101756-B :

I have fixed the broken switch on the PCB and checked the batteries. I now have a red led lighting when the switch is depressed. However, this does not operate the central locking or I presume turn on the alarm.

Comparing mine with the picture below I do not have the grey/black box thing in the bottom right hand corner next to the battery. Is the central locking/alarm transponder?

I am confused as to next steps. As all threads I can find on here and mentions on here talk about a 4 digit code (No I do not have it!) and a courtesy light console with an LED and a button. Along with an alarm key. I do not seem to have these fitted to my car. Though the Ultrasonic sensors and a rectangular box connecting them are in the roof console.

I thank you if you have stayed with me this far and hope you may be able to help me out.

PS is there anyone living in the Bristol area with a VAG cable and FIAT software so I can cancel my airbag light. A few beer tokens will be available .

 

[Ziggy122]

yes that funny rectangle with a rounded corner piece of plastic is the Immboliser Transponder

on the ingition barrell you will have Antenna/Ariel, the car talks to the key to confirm its the right key to start the car

if the car and key work - Engine starts
If the Key dont' give the right answer - the car locks the Ignition and fuel supply
So when you turn it over - it just keeps turning over and over till you run the battery flat
OR you take the key out and back in again
And the process of the key and car talking starts again

As for why the Key wont open the car - it might be a case of the key wasn't programmed that way for car use - ie a cheap key to flog the car with?

Ziggy

 

[billy bunter]

The blue key opens and starts the car.
It manually (in the door lock) operates the 2 doors.

BUT not pressing the switch on the key's fob.

Hence my question.

From your answer I need to get a transponder (the funny grey thing).

If I get a new transponder can I/ how do I make it work with the car?

 

[Ziggy122]

they key works without a transponder in it?
thats weird....
Unless its had an Uncoded ECU put in - removing the immbo side of it all

Im comfused as to why it doesn't have one

is the other key on the key-ring when you start the car - if so remove it leave it in the house, and try again

But There are 3 elements to a Key
The Blade - its mechanical to the car for the locks
The Transponder - For the Immboliser
The Chipset - For the Central locking

Ziggy

 

[interlock]

The key looks ok and has all the innards it should have, it seems to be a FIAT part, the number is correct. In the previous replies, The Transponder will allow the engine to recognise the key and start, and The Chipset controls the pulse from fob to the central locking, which you say works, and the red transmit light responds (like a tv remote).
I think you need to check the car body not the key. Make sure the c/l fuse and wiring are ok and that the door locks/alarm will respond to a signal from the controller.

 

[billy bunter]

I will put up some pics of my current key.

I only have one key.

 

[billy bunter]

Hi All thanks for the help so far. The pictures in the thread above are from an advert on ebay.

This is MY blue key.

As you can see compared with the one in the thread posted earlier I have no grey thing next to the battery. However I do have what looks like an RFID type device under the PCA. I presume this is performing the Immobiliser side of things.

 

[Ziggy122]

Right Based on your picture
The top half has the Grey plastic bit in it - thats the Transponder for the Immboliser
The Chip you've got sat between them is the PCB for the Remote cental locking
And the bottom is the battery and Mechanical Key

If they remote is working - as said red light comes on
Then the problem is most likely with the car next

Ziggy

 

[billy bunter]

interesting. What next? As I have not a clue and all info I can find on this is very confusing.

 

[interlock]

What he says. You could try a new fob battery if you haven't already.
Check fuses, interior #38? receiver module, wires etc. has previous owner disabled it/removed it/ broken it. Multimeter time by the sound of it.

 

[reddy4bed]

Push the button on the key fob, if it flashes then the key is ok.
Push the button/hole-button on the receiver, if it flashes the receiver is ok.
Push the button on key whilst watching the green LED in receiver, if it lights the key is communicating with the receiver. If it does not light, the key and receiver are out of sync.
To get receiver in sync you need the unlock code, you may be able to get it from Fiat security, though usually not, and it will cost you a fee to find out that its not there!.
Unlock code can be recovered from key pcb or receiver pcb, - its easier from the key. PM me if you want further help with that.
Tony

 

[billy bunter]

Thanks gents for your replies. I have one problem though. I cannot see any LED's in the roof console. I presume this is where the receiver is!

2 pictures to show what I mean.:-

Apologies for the poor quality I was already late to pick up my daughter from school.

 

[reddy4bed]

The top pic shows a recess with 3 slots around the edge. I would suggest that a panel containing the receiver fits in here with a fly lead that plugs into the white multi-connector.
Tony.

 

[billy bunter]

Thanks for all the help so far

So thats why I get no response and do not have any LEDS.

Can I buy one from a scrapper and fit it? Obviously I will have to match up the codes.

Are there any other bits I would need to check for before I go to a scrapper?

The receiver is missing what else could be missing from the central locking/alarm system?