Smart 451 Programming

**craigeyboyz** · 15th January, 2015, 11:12 PM

Evening All,

I've got a Smart 451 used key with a PCF7941 new virgin chip on. As I do mostly 450 keys which can be simply reprogrammed to any car these ones obviously need a new transponder on to even start. Originally I thought I could just use DAS to program this new transponder in but no dice!

I've searched and learned alot from here and other places but I'm hoping someone can fill me in the blanks so I can put this to bed.

As I understand it, since I've replaced the chip....I need to pre-code the transponder before using DAS to code it. Bearing in mind all I do is Smart cars so I only use DAS but I'm happy to buy something that can do the pre-coding if some can explain what I'll need to do to get them to work in DAS.

Finally I'm getting the idea that even with this done, the best I'll get is a coded key but the remote won't work. Is that still the case now? Is there anything I can clone from a new key from MB or anything? Or do MB supply a new key that's already got the coding on for the VIN or something

Really appreciate the help

**autofan1965** · 15th January, 2015, 11:23 PM

You cant precode blank pcf7941. Remote should learn itslef durning key learning.

**simaservis1108** · 15th January, 2015, 11:26 PM

Hello,

You can't reuse the key like that,because the PCF7941 must be eeprom programmed,then prepared with transponder and remote data.
You can't read eeprom contents on the locked key,hence you can't rewrite to new key.

Regards,
Sima

**craigeyboyz** · 15th January, 2015, 11:35 PM

Originally Posted by autofan1965

You cant precode blank pcf7941. Remote should learn itslef durning key learning.

Tried that but wouldn't play. Like simaservis1108 says I was missing the pre-programming but sounds like I can't even clone a key!

Is it not even possible to get the immo side to work even without remote programming?

Thanks again

**craigeyboyz** · 16th January, 2015, 03:03 PM

http://www.digital-kaos.co.uk/forums...s-lost-376194/

What's the result here then if he can read the eeprom from the SAM unit? Can that info be used to flash the new PCF chip?

**paul_12345** · 16th January, 2015, 04:22 PM

Originally Posted by craigeyboyz

http://www.digital-kaos.co.uk/forums...s-lost-376194/

What's the result here then if he can read the eeprom from the SAM unit? Can that info be used to flash the new PCF chip?

you can not get the remote working at all on a new chip. you could get the immo side working with the correct precode

**craigeyboyz** · 16th January, 2015, 04:40 PM

Originally Posted by paul_12345

you can not get the remote working at all on a new chip. you could get the immo side working with the correct precode

Cheers Paul that clears it up. How do keys from MB work then? Precoded and setup for remote when they get sent?

**autofan1965** · 16th January, 2015, 04:50 PM

I advice you to start basics.

**bearheroes** · 16th January, 2015, 06:47 PM

almost 5,5 years, 5 posts and you ask for that info???
even if someone knew that info do you think that would share for free???

**audiomeca** · 17th January, 2015, 12:24 PM

Buy new original keys from dealer, is the one option a this time for code a key in this car ,and all run , start and remote function, you can buy one not original precode transponder , but not remote open run!!!!

You can code a new key with xentry if have the MASTER KEY if not only avdi can add more keys a this car

regards