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resync key fob ml320

141K views 42 replies 27 participants last post by  Stretch600Wdriver 
#1 ·
I have a 1999 Ml320 and I replaced the battery on the key fob. Now it doesn't work. I tried turning the key to second position, taking it out and then holding down the lock and pressing the unlock 5 times, but that didn't work. Anyone has any suggestions for an alternate way to resync?
 
#2 ·
You have a W163, right?

Your synch was not quite right. Try this. According to the WIS, the sequence must be completed in 10 seconds!

1. Insert the key into ignition and turn to position 2.
2. Remove the key, and press the LOCK button, and hold it pressed while simultaneously pressing the UNLOCK button 5 times.
3. Now release the buttons, and press either the LOCK or UNLOCK button once.

That should re-synchronise the key. :thumbsup: Let us know if it works for you.
 
#4 ·
Did you? That is not what you wrote in your first post. Read what I said carefully.

W163 is a MB body style, and engineering references usually quote that. It is shown the first 5 digits of your VIN. For instance a ML350 can be either W163 or W164, which are different in many ways.

Your post should have been in the W163 forum, which you can find if you scroll below this General Mercedes Benz forum.
 
#5 ·
I tried that procedure many times with no luck. I took it to the dealer and even with hooking it up to the computer system, they have they couldn't resync the key. Their story is that the key fob is old and will not synchronize any more and I'd have to buy a new key.After $60 for their time and $240 for the key I was finally out of there. A poorer man with a key.
 
#15 ·
Just purchased a well used 2001 ML320. Came with two fobs, neither work. I tried to resync them and on one of the keys the dome light turns on at the end of the resync process, but it still does not work. What would the next step in troubleshooting be? My console 'lock all' button works fine. Thanks!
 
#22 ·
I came across this thread on a search for why my older key wouldn't sync.

I have synced it a few times in the past successfully.

So I've been having problems with the key. The CR2025 (3V) batteries have only been lasting a few months, then a month, then a couple of weeks.

I have adjusted the contacts to no avail.

Fortunately, I had some spare CR2032 (3V) batteries. They are slightly thicker but not much so.

Tried them and it synced straight away first time.

I know this isn't a good 'technical fix', but it worked for me and might be an extra option if the basics have been tried.
 
#29 ·
Need Help

Hey everyone. I Have a 2001 ml320, I tried the re-syncing procedure and it works for one button push. I turn the key from position 0-2 back to 0, pull it out, press and hold the Lock button then press the unlock button 5 times, release them both then push either lock or unlock. my vehicle with lock if i press lock after i do the resync, but then nothing happens after that when i push any of the buttons. If i hold the lock button again and press the unlock button 5 times, release, then push unlock, the vehicle will unlock but then once again nothing happens. I am very confused and frustrated.
 
#30 ·
Thanks for this thread. My C 180 kompressor does not recognize the key fob in the ignition, although it works to unlock and lock the doors and de activate the alarm. This means that it will not even turn the key to any position. I tried all sorts of variations and here is what eventually helped me to drive the car home.

1) I interned the key into the ignition (no recognition of the key)
2) I pressed down lock button and pulled the key fob out while lock was still pressed.
3) I pressed the unlock button (while my other finger was still on the lock button) 5 times.
4) I re inserted the key fob into the ignition (with my finger still on the lock button) and this time it was recognized.
5) the key was now able to turn all the way and start the engine and that's how I got it to the safety of my garage.

The issue now it that when I switched it off it reverted to its original state. No key recognition at all. If I follow the procedure above though it starts.

How can I get it to work normally without going through this long process?
 
#32 ·
You're a legend

Keyhole, you seriously ROCK !!!!

I thought my key fob was broken. I changed the batteries (just bought the car) but still not working.

Was almost resigned to getting a new key and having it programmed, but your process worked a treat.

Now I have 2 working keys with remote unlocking.
 
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