S430AMG

I'm usually pretty diligent about starting my car every 3-4 days, but I'm flawed. Car died and I had to pop start it. Everything is good but my keyfob will not work (it only starts the car).

I checked the battery/signal and it's fine.I also checked fuse 58 but it looks good.

I did the keyfob 3 different reset procedures but nothing. Here is what I tried so farProcedure #1

1. Insert the key into the ignition.
2. Quickly remove key from ignition and within 10 seconds hold down the lock button.
3. Continue holding the lock button, and at the same time press, the unlock button five times.
4. Next release all buttons and press the gate/trunk button one time.
5. Your Mercedes remote should be synchronized. Test to see if lock / unlock functions are working.

Procedure #2
Pos 1> hold lock 5 sec >hold unlock 5 sec >Hold both for 5 sec > repeat in Pos 2

Procedure #3
https://itstillruns.com/reset-mercedes-key-7492936.html

Procedure #4
https://itstillruns.com/reprogram-me...e-5014706.html

I tried above multiple times, still no luck.

Any ideas what else I can do?

tusabes

the ability to start the car is completely separate from the remote function . You can have a key fob with a completely dead fob battery still work to start the car

Replace your key fob battery

wallyp

Try the IR method of lock/unlock - Point the end of the key with the window directly at the small black rectangle on the driver's external door handle from nearby, and hold down the lock button on the key fob for several seconds to see if the doors lock. Repeat while holding down the unlock button. The doors should unlock, the sunroof should open and the windows should roll down. If this works, the battery in the key is functional, and the problem is in the RF portion of the key or the car. If neither the IR nor the RF work, the problem is likely to be the fob battery or its connection. If you changed the battery, make certain that the battery is installed correctly, and that you have two batteries if required.

SilberGrau57

To expand a bit on the abbreviations: IR is InfraRed, or optical (light) based. That's why you need to point the transmitter in the fob at the receiver in the door handle. RF is Radio Frequency or electronic signal based, so fob can stay in your pocket to lock/unlock, when it operating normally of course.

S430AMG

I checked the battery first (sorry forgot to add that in). I used the phone camera to check for the light on the bottom of the key.

Both key batteries are good

So it looks like it works when I point it at the handle (close).

Sounds like the Antena is not getting the signal?

tusabes

Then likely your alarm siren box has failed , they contain a lithium battery which is not replaceable and fails around this age

buy a new siren box from the dealer , all used ones have an equally old battery

S430AMG

I just pulled fuse 61, and it wasn't blown. But when I put it back........it started working. Weird

PS. I did also redid all of the steps to resync prior to pulling fuse (but much quicker, within 10 sec). But when I tested directly after, it wasn't working.

Seems like pulling the fuse did the trick? I also pulled 2 other fuses (# 1 and #2 from the right side of the rear seat fuse box). #61 is 5th.

Thanks to everyone for your help!

wallyp

Occasionally the fuse blade-to-socket connection develops a bit of corrosion that might stop current flow - removing and inserting can clear such corrosion.

S430AMG

Must be it!

yovenim

Hey so the lock button on my key fob is not working. The unlock and panic button work perfectly fine and I replaced the battery. When pressing the Lock button, the red LED on the FOB lights up but the car does not lock. Any suggestions?

wallyp

Possibly a poor connection on the key fob LOCK button. Carefully cleaning the "rubber" contact and the copper connection point on the PCB (Printed Circuit Board) might help.
Possibly a failure of the LOCK solenoid valve in the PSE (Pneumatic Service Equipment) unit.