idf.bts

2003 E320 - Can I buy a used key and use it?

I have recently purchased a used 2003 E320, one of the keys works fine, the other only turns on the ignition, but the door locks and other features do not.

Can I buy a used key and reprogram it myself? Or is something similar possible?

Suggestions on a way to fix the key is also welcome.

Many thanks

tjts1

No

Andre91

Have you replaced the batteries in the second key? A key that works in the ignition but the remote functions don't work usually means the batteries are dead. The keys take two CR2025 batteries, make sure to get lithium. The cheap batteries don't last in these keys.

idf.bts

Yes, I have changed it with fresh batteries.

It seems like there is a problem with the circuit board or one of the embedded chips.

I am reading conflicting information about the topic. I suppose finding a used new ignition with 2 keys is an option. Is this more work/money than makes sense?

tjts1

No, the EIS ignition is coded to get her with the ECU, instrument cluster and a few other modules in the car. You would have to replace all of those together.

cetialpha5

If there's an electrical issue, try getting a can of electrical contact cleaner. Make sure the batteries are out for a while and just spray down the entire key. If that doesn't bring it back, just get one of those Tile lost key finders and put it on your keyfob. It's not cheap for a replacement key and make sure you put a bunch of other things with the key so it's harder to lose. I have two keys for both my cars and haven't lost one yet. I make sure to keep track of them as my keyless go keys are $500+ each, I think regular keys are more in the $250-$300 range from Mercedes. It's possible that a locksmith might be able to code a key cheaper. I think the older MBs have key copying software out there that lets locksmiths make duplicate but after a certain year it became much more expensive for the equipment.

ot1

Do you have keyless go? there are two separate part numbers if so, with and without. Are they the chrome sided FOB?

E55Greasemonkey

No.