Reprogramming S Class key after battery rewire

[dj_factor]

Today I have unplugged the the positive terminal of the battery to check for battery drain and noticed that my key doesnt work anymore. I guess i need to program it back. When i face it towards the sensor on the keyhole, I can lock and unlock, but when its not facing the sensor, I cant. Do i need to program it or something. If so, how can i do so, what are the steps. Many thanks

Ohh its a s320, 2001 model.
Thanks

 

[Diesel Benz]

Today I have unplugged the the positive terminal of the battery to check for battery drain and noticed that my key doesnt work anymore. I guess i need to program it back. When i face it towards the sensor on the keyhole, I can lock and unlock, but when its not facing the sensor, I cant. Do i need to program it or something. If so, how can i do so, what are the steps. Many thanks

Ohh its a s320, 2001 model.
Thanks

You mean the key starts the car fine but only unlocks/locks doors via IR from the door? Sounds more like your key RF receiver antenna issue. Odd it it appeared just after the battery job.

I assume it is the same with the other key? (unlikely a key issue anyway)

 

[Dieselman]

You mean the key starts the car fine but only unlocks/locks doors via IR from the door? Sounds more like your key RF receiver antenna issue. Odd it it appeared just after the battery job.

It makes me wonder if the battery drain is down to the RF reciever being faulty and disconnecting it has finally killed it.

 

[dj_factor]

Hello chaps, I dont think its due to the RF receiver, I have noticed that when I lock the car, the alarm activates and then I get flickering noise or noise after every few seconds from the rear passenger side of the car. The noise is very difficult to describe but seems as if something is switching onn or off.

The key still hasnt been able to work when not in range to the IR on the door. Is there a way to synchronise the key. Also the battery went dead again so I think it is some other issue.

 

[BlackC55]

There are a few control units under the rear seat.

 

[Diesel Benz]

Hello chaps, I dont think its due to the RF receiver, I have noticed that when I lock the car, the alarm activates and then I get flickering noise or noise after every few seconds from the rear passenger side of the car. The noise is very difficult to describe but seems as if something is switching onn or off.

The key still hasnt been able to work when not in range to the IR on the door. Is there a way to synchronise the key. Also the battery went dead again so I think it is some other issue.

So would you assume no noise from the rear passenger side when locking the car using the RF connection of the key (if it worked)?

How did you conclude that the RF connection from the key works but the key is out of sync?

If the battery runs flat when the car is parked, shouldn't you figure out how much quiescent current is it drawing and if too much, which control units are guilty?