Faulty Keyfob...
 

Good afternoon...
I have an MG ZT-T 120+, bought new in 2006 from Main Dealer in Scotland. We now live in Central Portugal and brought the car with us 10 years ago.
Yesterday the Keyfob that I use (Key1) would not open the locked car but the 'spare' which my wife carries (Key2) will function fully.
The keys are originals and have had their batteries changed once in their life. (The Valeo original Fob is not damaged in any way.)

I have had a good long look at the 'problem reports' in this Forum and am aware of the many fixes offered over the years. Disconnecting the car battery for 30 minutes did not solve the problem neither did the many 4 clicks on the fob buttons to synchronise key to BCU (or is it BCU to Key?)...


Once in the car Key1 will start the car and appears to function correctly.
This key will open the car via the driver's door lock and the security of the vehicle appears to be functioning, however the driver's lowered window will not close when the key in the door lock is operated.

I have changed the fob battery in Key1 to no avail.
This morning I took the car to my local ex-MG workshop and he put it on his T4, with me looking over his shoulder.
The initial tests showed no faults on the car and both keys are confirmed as valid. I have the original barcode tags for the keys and he confirmed that the keys are 'correct'.
Disappointedly, he was not able to get Key1 to function fully from the T4, and confirmed my own findings. His best offer to me was to obtain a new key which he says he can code to the car, if I understand him correctly.
He says that he can supply a new key at about €300 which is just about the same as in UK.
Please advise if this should be done, bearing in mind that I do have a fully functioning Key2 and Key1 which appears to work fully except for Remote Locking.
I will probably take over Key2 and demote Key1 to 'standby' in my wife's care as she rarely drives the MG as she has her own 'french' runabout...
Any thoughts, please?

Does the red light flash when pressing the keyfob buttons indicating that both switches are functional?

If you get yourself a copy of Toaf you can re-use a secondhand circuit board using Brian's (or was it Trevor's) hack. I recently did one for a local member. Spare circuit boards are usually available either new or secondhand on ebay.

eg: https://www.ebay.co.uk/itm/1x-MG-ROV...cAAOSwJyVdBlh9

Regards

Yes - Key1 - Red light does flash on operation of either of the 'plip' buttons.


I have looked at the link you provided and it could be a way to go but inserting the Key2 circuit board in to the Key1 fob does not enable the Security circuit via the buttons...

As I said in the original post, Key1 operates in every way correctly except via the 'plip' buttons, so all that remains I think is the 'chip' being at fault?


I found the following information on the web which could be useful to members . <https://manualzz.com/doc/24344914/ro...body-electrics >
I shall have a look at 'Toaf' and keep the thinking cap on as a way to go!

OK bit confused as to “the security circuit” and the “the chip being at fault” yet you say Key1 will start the car which means the chip is not at fault and you certainly don't need to pay that much to get this sorted.

As I understand it the circuit board and chip are two independent items, the circuit board talks to the BCU and the chip (stored in the back of the keyfob) talks to the immobiliser (EWS).

If the circuit board from Key2 operates the remote locking then it should also do so even if you place it in the key1 fob. It doesn’t even have to be placed in the fob, you can operate the remote locking with just the circuit board in your hand and pressing the micro switches with your finger. Sorry but this makes little sense to me, perhaps someone else can better advise.

Regards

UPDATE...
Vitesse, Your comment about the actual function of the 'plip' components was most informative.
I have now re-tested both Key1 & Key2 - Key1 operates the Engine Start but not the Security System.
Key2 circuit card (out of the 'plip') Operates the Security System, installing it in Key1 Plip and the Key1 is now working properly, therefore Key1 card is faulty...
Key1 card in Key2 Plip operates Engine start only and no Security operation.

I shall now go back to your post about purchase of spare cards...and their implementation.
Many thanks for now,
Kind regards,
Martin Jackson

Thanks for the update and appreciation. Here's a brand new circuit board that your local T4 can programme to your car: https://www.ebay.co.uk/itm/GENUINE-R...gAAOSwrTFdWnLh

A bit pricy but much less than your original quote.

If memory serves me correctly there are five positions or slots for the remote locking function, two have already been used, which leaves you with three vacant ones.

Good luck

Mike