Oval Pektron fob does not need re-syncing or re-programming when only battery is changed and fob worked prior to this change. Fob should start working again when you change the battery.
If tahta is not the case, can you check if battery is empty or did you put polarity in the correct order?

 

Thank you for your quick answer. the polarity is correct. the remote fob was 20 days without battery. I had sent it to the UK to renew the cover and the buttons

 

Can you check if battery is new?

 

yes she is new

 

Then it should work... Did you disconnect car battery in the meantime or you just waited for the fob?

 

I have not disconnected the car battery. I just received the fob

 

Then, if only fob cover and buttons were replaced, I cannot see the reason why fob should not work...

 

but is it necessary to disconnect the car battery? I do not know this procedure

 

DO NOT DISCONNECT CAR BATTERY IF ALARM IS SWITCHED ON, EVEN IF THE CAR BATTERY IS FLAT.

Connect some power to disarm the alarm before removing the car battery.

 

No, by no means it is not necessary to disconnect car battery. I was just asking to see if there is any reason why your fob should not work, and I cannot see any reason at this moment. Your fob should be working.

 

this was communicated to me who did the work of replacing covers and buttons:
" "Hi, I can confirm the remote is sending a signal, otherwise we would not have returned it back to you. As the battery was not inside when we received the remote it seems like it has lost its memory to the car, you will need to have it programmed back to the vehicle. Regards "

 

There is no any memory in the fob to recognize the car. Car alarm system has memory which recognize the fob. That is the reason I asked if you disconnected car battery, because in that case you could loose memory in car alarm system and car could not recognize the fob, but not vice versa.
At this stage fob should work if the car had battery supply all the time. Only question is if your car battery has enough power to supply electric systems or it is on its way out. You should check the voltage on your car battery withiut disconnecting it.

 

I have a second fob that works regularly

 

Make sure your working fob is well away from the car and try again with other fob.

 

I tried but it does not work

 

who did you send the fob to for refurbishment. was it a company called remote key. if so they are usually reliable and know there stuff. have you tried opening the case and pressing the buttons directly to see if it works then. maybe a duff aftermarket fob case not pressing on the micro switches underneath correctly.

 

s

I tried to press the buttons directly but it does not works

I sent the fob to Remote Fob Center UK. this is their answer:
"Hi, I can confirm the remote is sending a signal, otherwise we would not have returned it back to you. As the battery was not inside when we received the remote it seems like it has lost its memory to the car, you will need to have it programmed back to the vehicle "

 

I sent the fob to Remote Fob Center UK.

These people?

https://www.remotefobcentre.com/

 

do you know anyone that has the diagnostic equipment to reprogram this can be a garage or auto locksmith. this job is not too difficult with the right equipment and wont take to long.

 

It is not easy to reprogram used Pektron fob even with proper tools. You need barcode with each Pektron fob in order to be able to program it to alarm system. This barcode represents rolling code window in which alarm systsm can recognize the fob. If fob was pressed so much times in use, its rolling code will roll way out of this bar code window and you will not be able to recognize it anymore. So, reprogramming used Pektron fobs is not an easy job, if possible at all.

Since second fob is working properly, seems that alarm system did not loose its memory. That leaves us with non working returned fob, which should be working.

 

A little part of me thinks the OP got the wrong fob back.

 

that is possible suppose easy to mix up if they are doing a large number.but this is no excuse if they have made a mistake and you loose out after paying for refurbishment of a item that no longer works. would contact them again and explain item is not fit for purpose. someone else may have same problem if they have wrong fob sent back

 

Understood the FOB has a rolling code which changes each time the buttons are pressed, and the cars alarm system recognizes this. The rolling code is to avoid that any nerd intercepting the signal from the FOB can use the copy to get away with the car. So if the FOB is pressed with no working car around it gets out of sync. Thus for example playing with the FOB without the car around can create this error. Also if you have two FOB close together they start 'talking' to each other with confused codes as result.
Had once a similar issue after a battery change of the FOB. The stupid Dutch Rover dealer had to unpack the T4 computer he had never used before and after a day of testing he found that the new FOB battery was completely dead. Seems that these type of batteries can show a nice voltage when tested with a multimeter but completely collapse once some current has to be delivered. Same type of battery powers the clock on the motherboard of a PC and had the same strange thing happening there.
So get a GOOD Quality battery (not the cheapest one on ebay), put it in the FOB and give it a try.

 

I write to Remote Fob center to ask for confirmation

 

first of all thanks to everyone
now

for scruple I replaced the fob's battery with a new Varta but it does not work.
Is there a procedure to resynchronize the fob?

 

on the previous type of key fob the re sync was as follows. lock door remove fob battery press buttons 10 times to remove power from circuit board. refit battery. open door with key but do not open door. then press lock button on fob until door locks this is usually about 5 times. not sure it will work on the newer oval fobs but worth a try. if still no success contact the company who done the work. if you want to double check contact www.remotekey.co.uk. they know absolutely everything about key fobs on all cars. you should also be able speak to them direct by phone number on there website.

 

unfortunately it does not work. anyway thanks to everyone for the time you have dedicated to me. gianni

 

That's why I am asking.