Passat 365 Keyless and Remote don't work after battery replacing

[kostelectronics]

Hello all,

I have a customer with a Passat 365 (B7), 2011 year.
I changed the starter-battery from the car. Now the customer states the keyless and go does not work at all, the remote works only when he's really close to the car (touching the driver's window glass).
The key was replaced 6 months ago and it's nearly brand new. The owner has only one key to this car, so i can't compare it with a 2nd key.

How is that possible? did i kill the CEM when installing the battery with some sparks? This car have more than one antenna for keyless/remote installed.

Question: How to check the CEM for good signal reception? can i use a key from the scrapyard and only learn the remote to check if the key or the CEM is dead?

Any good ideas to help me?

BR Matthias

[Weasel3]

Hello all,

I have a customer with a Passat 365 (B7), 2011 year.
I changed the starter-battery from the car. Now the customer states the keyless and go does not work at all, the remote works only when he's really close to the car (touching the driver's window glass).
The key was replaced 6 months ago and it's nearly brand new. The owner has only one key to this car, so i can't compare it with a 2nd key.

How is that possible? did i kill the CEM when installing the battery with some sparks? This car have more than one antenna for keyless/remote installed.

Question: How to check the CEM for good signal reception? can i use a key from the scrapyard and only learn the remote to check if the key or the CEM is dead?

Any good ideas to help me?

BR Matthias

Very strange.
But maybe, by programming the key one more time. By OBD.
It will sync up the modules again.

Only PIN is needed on this key.
Since its already a dealer key.
Prepared to the car.

[kostelectronics]

Thank you!

somehow it makes no sense to me. If the remote is not synchronized, it will not work at all. This here works but only directly by the car. it must be something signal strength related!
The Keyless whould work i guess when the RF signal transmission whould be OK i guess.

I'm not familiar with the "newer" immos like this ;) I'm not a Locksmith and have very limited tools for this. I have only a xTool Pad II which is complete garbage.
I don't think it will read the immo Pin, but i will give a try. Otherwise i desolder the EEPROM from the CEM and post here that somebody can extract the pin.

Thank you very much so far!
BR Matthias

[AndyCZ]

Did you try resynchronize remotes in door handle with emergency key lock unlock and then press any button on keyless key?

[kostelectronics]

I will try again, maybe i made it wrong. But i didn't expect that it will work because i'm pretty sure it's a RF problem. Whould the remote work only near the car if it's not synchronized? Me as a dumb man whould say no, but i need inputs from experts in this case.

BR Matthias