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Discussion Starter #1
Hey guys, i just bought a w210 e55 amg from the auctions, and i've been loving it so far.

the key fob included didnt work, but the flat 'master' key works perfectly so i've been using that

the key fob was flashing light, and the LED at the front would flash when i looked at it from my phone camera- but it wouldnt do anything. it wouldnt lock or unlock the car, or start it, nothing.

i opened it up and took a look at the chip and somehow one of the the cpu(?) pins broke off, so i tried to resolder it and it still doesnt work.

$200 for a new key fob from mercedes, so i was wonder if there's anything i could do otherwise? maybe the solder wasnt good?



 

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Yes, $200 is CHEAP. Get it now while they're still honoring the price.

Around here its $300+, with some dealers charging past $400 for a key.
 

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The pin is IRQ/ VPP. Used for programming. So it is likely not so relevant. As long as you press the keys, and for each key pressing the IR LED flashes on the phone screen, there is hope.

I assume the key is not turning in the ignition. I would first tackle by checking the metal posts on the tip of the coil that surrounds the IR receiver and transmitter in the front. Usually the coil wire terminations come off and need to be soldered. You can measure the resistance of the coil from the posts.

Once you ensure continuity on the coil posts, move to the sides of the coil where the posts are connected to the PCB traces. Sometimes the traces crack due to torsion applied to the key over time. You can reflow the solder to ensure good electrical connection.

You can try inserting the PCB without cover (and the battery tray), as it does not need batteries to unlock the ignition. If you can hear the steering lock clunking to unlock, you can put the PCB into the case, and install the batteries with its tray.

The door lock / unlock will not work via the fob till you achieve synchronization of the codes. And you can only do that if you have a key that you can insert and turn (authorized). Once you can do that you leave the key for a while and it should synch (not sure if you had to press one of the keys but this is the second stage. You need to get the ignition part fixed first).
 

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Hey guys, i just bought a w210 e55 amg from the auctions, and i've been loving it so far.

the key fob included didnt work, but the flat 'master' key works perfectly so i've been using that

the key fob was flashing light, and the LED at the front would flash when i looked at it from my phone camera- but it wouldnt do anything. it wouldnt lock or unlock the car, or start it, nothing.

i opened it up and took a look at the chip and somehow one of the the cpu(?) pins broke off, so i tried to resolder it and it still doesnt work.

$200 for a new key fob from mercedes, so i was wonder if there's anything i could do otherwise? maybe the solder wasnt good?



$200 is cheap get it!!!!

I also sell keys for $400,

Dealer in my area is like $360
 

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Discussion Starter #6
it's a 1999 e55 amg.

The pin is IRQ/ VPP. Used for programming. So it is likely not so relevant. As long as you press the keys, and for each key pressing the IR LED flashes on the phone screen, there is hope.

I assume the key is not turning in the ignition. I would first tackle by checking the metal posts on the tip of the coil that surrounds the IR receiver and transmitter in the front. Usually the coil wire terminations come off and need to be soldered. You can measure the resistance of the coil from the posts.

Once you ensure continuity on the coil posts, move to the sides of the coil where the posts are connected to the PCB traces. Sometimes the traces crack due to torsion applied to the key over time. You can reflow the solder to ensure good electrical connection.

You can try inserting the PCB without cover (and the battery tray), as it does not need batteries to unlock the ignition. If you can hear the steering lock clunking to unlock, you can put the PCB into the case, and install the batteries with its tray.

The door lock / unlock will not work via the fob till you achieve synchronization of the codes. And you can only do that if you have a key that you can insert and turn (authorized). Once you can do that you leave the key for a while and it should synch (not sure if you had to press one of the keys but this is the second stage. You need to get the ignition part fixed first).
im getting continuity on the posts, and where it connects to the PCB it looks good and there's continuity there too. still doesnt unlock the car or turn ignition... everything else on the PCB looks like it's been soldered pretty well. i'll try reflowing though.
 

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The traces are under the posts. That is where it cracks. Follow the tracks on the PCB to a plated thru hole or a pin, and measure continuity there.
 

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If the traces from the red marks are connected to the capacitor, why do you not think it matters ? If the traces end up across the capacitor you should also have a continuity across the yellow.

Measure continuity red to yellow at each side to determine which side has discontinuity. Then jumper the bad trace and test.
 

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Discussion Starter #11
If the traces from the red marks are connected to the capacitor, why do you not think it matters ? If the traces end up across the capacitor you should also have a continuity across the yellow.

Measure continuity red to yellow at each side to determine which side has discontinuity. Then jumper the bad trace and test.
on the right side in the picture, red does not have continuity with yellow. so maybe it needs more solder?
 

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Just solder a thin wire between the yellow and red at the disconnected side, and see what happens. The trace may have been broken with no bare metal exposed under the post that reflow may not work.
 
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