How to Program key

[supadupa64]

I have a couple cut keys that open the doors and I'd like them to also start the vehicle. Surprisingly, when I first got them cut they both started the car. I had my original key with me so that must have been it? They don't start the car any more.

Anyway, is there a way to program they keys so they start the car?

I've already read through ways to program the fob which haven't worked yet.

 

[colb]

There are two distinct systems inside the key fob, the first is a transponder chip embedded inside that is coded to the EWS module in the car, when inserted into ignition the transponder is read and if the code in the key is correct and another rolling code the car gave the key the last time it was used is correct it releases the starter and allows the car to crank.
The second system inside the key is the pcb that the buttons work for locking and unlocking. All keys have to be synced to the car imediately after each other. A search of the forum will find details of the syncing methods to do this. As to coding keys to produce cranking keys you can get an AK90+ Key coding machine for use with a laptop but I found I couldn’t get it to code my keys. Blanks if obtained from eBay with the correct transponder inside will of course need to have the blades cut by a key cutter. Not all will cut customer supplied keys, stay away from the likes of Timpsons find an independent shoe repair and key cutter. When it comes to testing keys as to if they crank or not make sure you leave sufficient time between inserting the keys as the car will retain the code from a good key for a short time and if a bad coded key is inserted too soon after a good key it will allow the car to crank. Subsequent tries will fail to crank. The EWS module is behind the o/s footwell side panel and has to be taken out for the system to be read by the coding software with the AK90+ or locksmiths equipment. Mobile locksmith charges around £120ish for 1 key to be coded may be more if they supply and cut.

 

[Sticks]

Thanks, that's useful information. I have the two original keys and one's started not cranking intermittently.

 

[colb]

The battery inside these original keys are rechargeable and get charged when inserted in the ignition. The battery has no bearing on the no crank you have as the transponder is not powered, the battery only operates the central locking functions. Try leaving the non working locking keys on a toothbrush charger overnight and see if that puts some charge into it then try syncing both keys. Not sure why you get a intermittent cranking key if the other key works ok.

 

[Sticks]

Thanks. I try both keys and the other day the 'bad' one worked and got a 30 mile/1hr drive. Is that enough? I'll check the age of the car battery too as the radio presets weren't working today but I don't think it's that old. Thanks for your input.

 

[colb]

Yes checkout the car battery and check out what the alternator is putting out with the engine running, you should be seeing around 14volts if it’s good. Degrading main battery can cause all sorts of electrical issues even though they can start the car

 

[BabyTiger]

I can code the transponder chip, it sounds like you don't have it in the key that you have cut.

 

[supadupa64]

I can code the transponder chip, it sounds like you don't have it in the key that you have cut.

Ok so how do you do it?

 

[Jfgoldfish]

Ok so how do you do it?

The cheapest and most common way to diy program transponder chips is with an Ak90 programmer.
Be aware that this involves removing the EWS module from the car and flashing one of the chips on the board. A mistake during this process could leave you without any working keys so some knowledge of proper handling of bare PCBs is required.
Very doable though. Just need to follow the instructions accurately.

 

[colb]

If you go for an AK90+ key coder attached to a laptop I wish you better luck than I had in coding a key. Had blanks obtained from ebay cut by a local key cutter then used the AK90+ kit to code the keys without any success, it could not read the processer chip on the EWS board no matter how many times I cleaned the contacts. Had to admit defeat and engaged a mobile locksmith to come and sort it out. He used a far more sophisticated bit of kit to read the eeprom on the board in the EWS and coded the key to a vacant slot, that failed to produce a cranking key. Recoded the key to a slot that was already in use but which I didn't have a key for, result a cranking key. Cost me £130. I now have 2 keys and a third key which I can transfer the transponder to if I ever need to replace the new key. The original key is sealed so unable to open it up to access the transponder as easily as the fresh cut ebay key.

 

[supadupa64]

If you go for an AK90+ key coder attached to a laptop I wish you better luck than I had in coding a key. Had blanks obtained from ebay cut by a local key cutter then used the AK90+ kit to code the keys without any success, it could not read the processer chip on the EWS board no matter how many times I cleaned the contacts. Had to admit defeat and engaged a mobile locksmith to come and sort it out. He used a far more sophisticated bit of kit to read the eeprom on the board in the EWS and coded the key to a vacant slot, that failed to produce a cranking key. Recoded the key to a slot that was already in use but which I didn't have a key for, result a cranking key. Cost me £130. I now have 2 keys and a third key which I can transfer the transponder to if I ever need to replace the new key. The original key is sealed so unable to open it up to access the transponder as easily as the fresh cut ebay key.

Interesting. Keysmith told me if they couldn't program it they would still charge me.

My two cut/unprogrammed keys both started the car when I first got them. Then later they didnt. Strange.

 

[colb]

Have you lost the small rectangular transponder inside the two keys that no longer crank the car, this can happen if they are of the type that can have the fob opened to access the printed circuit board inside that operates the central locking functions of the key with the buttons. Had it happen to one of my replacement keys when it fell apart on me when sitting in the car, lucky I noticed as the transponder fell out onto the carpet, retrieved it and used a dab of glue to secure it back inside the fob and then clipped the two halves back together.
The AK90+ machine will also read keys so you can see what key slot it has been coded to but that will depend on whether the transponder chip is still in the fob and not been lost. Since you have cut keys that work the locks you could try new transponder chips and try programming them using the AK90+ kit but that still involves reading the EWS module by plugging onto the processor on the EWS board.
Transponders available on ebay 433mhz PCF7935 chip, key blade type HU92.