Audi A6 4G keyless start

[mislav88]

I have 2012 A6 with keyless start (not keyless entry, only start) not working. It says key not recognized with both keys, only starts when key is put on dash where key logo is.
Dealer tried to re adapt keys, change battery, but still the same.
Remote locking works fine, and there is no single DTC in car.

Where to start with this one, BCM2 fault, antenna?

[haroutioun]

I have 2012 A6 with keyless start (not keyless entry, only start) not working. It says key not recognized with both keys, only starts when key is put on dash where key logo is.
Dealer tried to re adapt keys, change battery, but still the same.
Remote locking works fine, and there is no single DTC in car.

Where to start with this one, BCM2 fault, antenna?

Hello.
1) please tell me,you mean when you insert the remote key in ignition he start, but if you leave some where it in the car, and cant start the car by using push start bottom? this you mean?

[mislav88]

yes, only there is no ignition slot but you just hold key by the key mark near the cd (this work even with battery out, guess there is just a simple transponder read coil)

[haroutioun]

Hello.
OK i understand.i think not BCM2 problem,this antenna problem,did any body dismount the doors to check if sound system stop or central lock window?,i am asking cause always i am getting same problem, and that was the problem when they reconnect door accessory lick speakers connector,so here the connector of speakers & antenna of key-lees are same look,so try check them,maybe some who insert this wrong place.

[mislav88]

i will check that, where is antenna located? note that this car does not have keyless entry, so no antennas in door handles.

[haroutioun]

i will check that, where is antenna located? note that this car does not have keyless entry, so no antennas in door handles.

Hello.
1) i just load this pics of location antenna with R138 + R139 + R200 + R201.
2) you can re-sync your remote (4G0 959 754 K) but by obd2, but in your past post you try at the dealer sync no? and no result,so i don't know what tool you have in your hands, you can test in (Meas.Blocks) the antennas,if you have odis this tool he can help you step by step to arrive at solution.

[mislav88]

a little update, there is no antenna in doors as it has only keyless go, not keyless entry.

i also noticed that when you press start engine button led on key flashes a few times, and then i get "key not recognized" on dashboard.

is there a way to resync it?

[mislav88]

yes dealer deleted the keys and re adapted them again. i have vcds, vas and odis.

[alin175]

Hi guys, I bought yesterday and A6 c7 2012. It has 2 remote keys and both of them need to be placed on the dashboard in order to start the car. I changed the battery in one of the keys and it's doing the same.. any thing I can do or just go back to dealer? Cheers

[simaservis1108]

Flash in PCF7945AC is corrupted.
Only solution is to reflash PCF7945AC or new Keyless-GO key.
Change your batteries more often.
If battery goes below 2.8V brownout failure happens when you press the buttons,and flash gets corrupted.
Same as Audi A4,you code in the remote,the remote gets accepted but nothing happens on button press.

[alin175]

Flash in PCF7945AC is corrupted.
Only solution is to reflash PCF7945AC or new Keyless-GO key.
Change your batteries more often.
If battery goes below 2.8V brownout failure happens when you press the buttons,and flash gets corrupted.
Same as Audi A4,you code in the remote,the remote gets accepted but nothing happens on button press.

is this for my problem or for some one else? When I press start the key led starts to blink , and after 2-3 sec it's asking to place the key on the dashboard. Any idea how much is a new key? cheers