Key fob not working - 2001 Mercedes-Benz ML 320

limited info generic answer check and test battery -- most likely the key fob itself is failing you can have some one test fob or get another fob[s] and have programmed

1. How do I program my Dodge key fob without working one?"); display: inline-block; height: 24px; width: 24px; margin-top: -1px; transform: rotateZ(-180deg);">
   How do you program a key fob without original?
   
   1. Replace the batteries inside the key fobs.
   2. Get inside the car.
   3. Turn on the ignition.
   4. Press the lock button on the remote key.
   5. Listen for a Lock Sound.
   6. Programming additional remotes.
   7. Turn off the ignition.
   8. Step out from your car and test the result. How to program my Chrysler key fob without working one Turn the ignition key to Accessory or "ACC". Turn the ignition key off again, and the door locks will cycle once. Press any button on the key fob 3 times in a row to program it. The door locks will cycle once again once programming is complete. https://northcoastkeyless.com/2008-chrysler-300-keyless-entry-remote-fob-programming-instructions/ the instructions to [program a fob are that you need two or need to have dealer or approved locksmith

The key fob will need to be reprogrammed to the vehicle since when the battery was replaced in the key fob, the key was reset. This is why nothing is working with the key fob. After replacing the battery in the key fob remote, you will need to reprogram the remote to the vehicle

Sounds like the key fob is going bad and needs replaced.

How to Program a Key FOB for the Chevy ' eHow.com

www.ehow.com/how_7508133_program-key-fob-chevy.html

How to Program a Key FOB for the Chevy ... your Chevy, if you obtain new or replacement keys they will need programming to work with ... How Do I Program MyKey Fob? ...

Try with brand new key fob battery and see.If that helps.
Otherwise May be keyfob needs to be reprogrammed.

KEYFOB PROGRAMMING

Keyfob remote reprogramming is not very difficult but on some cases it can be done by dealer service tools.

If the remote s faulty then key fob will not get programmed.

Insert the key in ignition. Turn the key to on position, and cycle the key three times off-on-off-on-off-on. Then with the key fob remote select your remote and then try to operate the vehicle with remote.

These are just the basic procedure, but sometimes it will not help.

On that case dealer is the only option.

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There are few much related troubleshooting links mentioned below for remote key fob reprogramming. I suggest you to go through the list and click the link below to go through its details and procedure: -------

2009 Toyota Highlander: Smart Key Not getting Detected?

http://whatisbyme.blogspot.in/2012/05/2009-toyota-highlander-smart-key-not.html

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2007 Toyota Prius: Reprogram Remote Keyfob?

http://whatisbyme.blogspot.in/2012/05/2007-toyota-prius-reprogram-remote.html

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Pin that holds the flick key part to the key fob?

http://whoisbyme.blogspot.in/2012/07/pin-that-holds-flick-key-part-to-key-fob.html

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2006 Toyota Hilux: Programming New Key?

http://technoanswers.blogspot.in/2012/04/2006-toyota-hilux-programming-new-key.html

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Where is Key chip memory located on 2004 ford Freestar?

http://technoanswers.blogspot.com/2012/01/where-is-key-chip-memory-located-on.html

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Ford Keyless Remote Fob Reprogramming?

http://schematicsdiagram.blogspot.com/2011/12/ford-keyless-remote-fob-reprogramming.html

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After getting car washed, check engine light is ON and key less entry not working, tried reprogramming. Also car shows fuel pressure?

http://schematicsdiagram.blogspot.com/2011/12/after-getting-car-washedcheck-engine.html

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Audi A8 Key Fob Programming?

http://technoanswers.blogspot.com/2011/12/audi-a8-key-fob-programming.html

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Oldsmobile Aurora Key Fob Reprogramming?

http://technoanswers.blogspot.com/2011/12/olds-aurora-key-fob-reprogramming.html

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Buick Lesabre Key Fob Reprogramming?

http://technoanswers.blogspot.com/2011/12/buick-lesabre-key-fob-reprogramming.html

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Keyfob remote not working on 2003 Ford E350 Econoline?

http://technoanswers.blogspot.in/2012/01/keyfob-remote-not-working-on-2003-ford.html

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KeyFob will open the doors but not start on BMW?

http://technoanswers.blogspot.in/2012/02/key-will-open-doors-but-not-start-on.html

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Mitsubishi Car Key Not getting detected after replacing ECM

http://repairhelpcenter.blogspot.com/2012/11/mitsubishi-car-key-not-getting-detected.html

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Key Fob will not lock and unlock doors?

http://technoanswers.blogspot.in/2012/02/key-fob-will-not-lock-and-unlock-doors.html

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2000 Jeep Cherokee Limited: KeyFob Remote Not Working?

http://schematicsdiagram.blogspot.in/2012/06/2000-jeep-cherokee-limited-keyfob.html

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Chevrolet Malibu: Key Stuck in ON position?

http://technoanswers.blogspot.in/2012/04/chevrolet-malibukey-stuck-in-on.html

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Theft indicator not letting car to start?

http://technoanswers.blogspot.in/2012/02/theft-indicator-not-letting-car-to.html

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2012 Dodge Ram: Ignition Key will not release?

http://whoisbyme.blogspot.in/2012/07/2012-dodge-ram-ignition-key-will-not.html

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These details will help.

Thanks.

I have a few troubleshooting tips for your #Toyota Avalon key fob.

First things first, make sure it's YOUR key fob (and you didn't accidentally grab your mom's keys!).

Change the battery
Batteries don't last forever, you'll be surprised how often it's just a dead battery! Search our YouTube channel on how to change a key fob battery for your specific year, make, and model!

Wipe the board
The board inside your remote can get a lot more filthy than you think! When the board is dirty it can prohibit the contact to the circuit board when you push down on the button. Simply wiping the circuit board off can make your key fob like new again!

The old car battery reset trick
I know this sounds absurd, but it works sometimes and is worth trying. If you exhausted all of the options above, disconnect both terminals on your car battery for 10 minutes. Then reconnect them and try your key fob. This has worked for many people and I have no idea why. If you do, please comment below to explain.

New fob!
It might be time for a new key fob! No need to dread over the expensive costs of a new key fob, at Keyless Entry Remote Fob Inc., you can get a refurbished one for a very affordable price! You won't even be able to tell the difference. Just search your vehicle make, model, and year to purchase a key fob or give us a call at 402-671-5100.

First thing, does the red light on the remote light up when you push any of the button
if no, then replace battery inside remote
if yes, then try repograming the remote to the car again.
-Have both remote ready. fob#1 and fob#2 (doesn't matter which one is #1 or #2)
-each step has to be done within 5 sec or it will not work, but don't do it super fast.
1.turn key just to the "on" position (not starting) and push "lock button " on fob#1 once and release
2.turn key off
3.turn key just to the "on" position (not starting)and push "lock button " on fob#1 once and release
4.turn key off
5.turn key just to the "on" position (not starting)and push "lock button " on fob#1 once and release
6turn key off
7.turn key just to the "on" position (not starting) and push "lock button " on fob#1 twice (if you only have one fob, then stop here and go to step 7)and push the "lock button" on fob#2 twice.
8.turn key off and remove key from ignition.
if you did it right, remotes should work again.
good luck

There are a few things you can do to get your key fob working like new again:

1) Wipe the board
The board inside your remote can get a lot more filthy than you think! When the board is dirty it can prohibit the contact to the circuit board when you push down on the button. Simply wiping the circuit board off can make your key fob like new again!

2)Get it checked
Go to your local hardware store like AutoZone or Oreilly's. They usually have a RF frequency tester. This little gadget will let you know if your key fob is sending a signal. If it is, you may need to reprogram your key fob to your vehicle

3)The old car battery reset trick
I know this sounds absurd, but it works sometimes and is worth trying. If you exhausted all of the options above, disconnect both terminals on your car battery for 10 minutes. Then reconnect them and try your key fob. This has worked for many people and I have no idea why. If you do, please comment below to explain.

4)New fob!
It might be time for a new key fob! No need to dread over the expensive costs of a new key fob, at Keyless Entry Remote Fob Inc., you can get a refurbished one for a very affordable price! You won't even be able to tell the difference. Just search your vehicle make, model, and year to purchase a key fob or give us a call at 402-671-5100.

The buttons on the key have gone out. Check with your dealer for another key fob.