CLS key fob reset

[MBCLS100]

2013 CLS 250. Sat for 14m. Both batteries dead and have been replaced also new fob battery.
had to use mechanical key to open the car but nothing happens when I put the fob in the ignition. Is there a reset protocol to get the fob to recognise the car and vice verser?

 

[DSM10000]

2013 CLS 250. Sat for 14m. Both batteries dead and have been replaced also new fob battery.
had to use mechanical key to open the car but nothing happens when I put the fob in the ignition. Is there a reset protocol to get the fob to recognise the car and vice verser?

Has the car battery been fully recharged?

The fob batteries have nothing to do with releasing the steering lock or deactivating the immobiliser to start the car.

The key is detected by the steering lock and the immobiliser circuit in the key is powered by induction from a coil in the steering lock / ignition switch.

 

[MBCLS100]

Both new batteries are fully charged.
The fob cannot unlock the doors but it turns in the ignition switch but no lights on the dash

 

[DSM10000]

Both new batteries are fully charged.
The fob cannot unlock the doors but it turns in the ignition switch but

Who changed the two batteries in the car?

Are you 100 %confident that they were connected correctly?
Also, are you sure that the protective cover was removed from one of the terminals on the batteries in the key fobs?

Easily overlooked. Guess how I know?

As said, the batteries in the key fob are for powering the RF signal for the lock /unlock. Not for starting the engine.

From your description you may have two problems. I assume that you have tried both keys in the ignition?

It is possible that there is a fault with the Electronic Ignition Switch. (EIS), this is not uncommon.

 

[DSM10000]

Are you able to check the voltage under the bonnet? There is usually a Positive terminal for attaching jump leads.

 

[MBCLS100]

The fob battery has the film removed, already know about this, guess how!
Main battery and auxiliary battery both giving a good 12v reading (checked fob battery as well 3v). I have no way of testing the main battery under load for Amps but that’s academic if I can’t turn the engine over.
I’ve also checked fuses / relays

 

[DSM10000]

During the period it wasn't used could there have been damage to wiring from rodents?

 

[MBCLS100]

The fob battery has the film removed, already know about this, guess how!
Main battery and auxiliary battery both giving a good 12v reading (checked fob battery as well 3v). I have no way of testing the main battery under load for Amps but that’s academic if I can’t turn the engine over.
I’ve also checked fuses / relays

During the period it wasn't used could there have been damage to wiring from rodents?

It’s possible as I’ve had that issue before but I can’t see anything obvious

 

[DSM10000]

Have you checked the main engine earth connection and all of the fuses in the front and rear SAM's?

I don't have any diagrams of them but it may be worth a check as well as looking at any exposed wiring looms for signs of damage.

 

[MBCLS100]

I’ve spotted some damage to the loom. It happened before when it started to run really rough, auto electrician found damage to one of the injector feeds.
I will ring him tomorrow and get him to come out.
Thanks for your advice.