Reprogramming W208 keys

[verytalldave]

Thats handy.

All it needs is one dodgy connection on the chip and that's the likely result.

As I said, this modification is only for the brave.

 

[wardpaa]

I have checked all of the connections from each pin to where the track goes to on the PCB. I took a photo of the board after removing the old chip so was able to check continuity after fitting, by tracing where each track goes. Some run under the chip then to the other side of the PCB, so when the chip is fitted you would have no way of knowing.
With everything working exept the immobiliser (doors, boot, Infra-red, remote wiindows) I reckon the key fob is OK, but there is something else to be done.
I will speak to a specialist tomorrow to see if STAR is involved.

 

[A-AvantGarde]

I will speak to a specialist tomorrow to see if STAR is involved.

I don't believe Star is required - good luck and please keep us posted...

 

[verytalldave]

Have you tried a new battery?

 

[wardpaa]

yes Dave. Tried the batteries from the old remote that were reading just over 3V each. Made a bit of difference to Infra Red fange but thats it. Lockking appears to be the only person on this thread with a fully working key and a W208. Hope they didn't change anything on the W209 thats stopping mine from working.

 

[Diesel Benz]

With everything working exept the immobiliser (doors, boot, Infra-red, remote wiindows) I reckon the key fob is OK, but there is something else to be done.

Can you clarify which functions are working and which are not. I interpret doors, IR, remote windows are working but then you don't mention if the car starts or not (which is pretty important to me), do I interpret your list incorrectly?

I was just wondering if you actually have a US frequency key and the RF part would not be working with your car?

 

[wardpaa]

Correct, the Key works with entry (doors, boot, Infra-red, remote windows) but when you insert the key into the ignition, it will not let you turn it.
As I understand, the RF part opens the car and the Infra red does the ignition and remote windows. If I had the US version I would also have a panic button too.

 

[A-AvantGarde]

The car unlocks using both infra red as well as RF.

Can you unlock ther car from all sides, passenger side, front & rear of vehicle too. On the W203 and W209 I believe there is only one IR receiver in the drivers door handle.

Would be interesting to know if the unlocking via RF is working.

 

[Baron_Samedi]

Just for info, MY2006 (55 plate) only have the IR transponder in the drivers door.

 

[verytalldave]

Is it possible the chip got damaged in the changeover?

Would it be a silly suggestion to put the chip back into the original key to see if it works then?

 

[A-AvantGarde]

Correct, the Key works with entry (doors, boot, Infra-red, remote windows) but when you insert the key into the ignition, it will not let you turn it.
As I understand, the RF part opens the car and the Infra red does the ignition and remote windows. If I had the US version I would also have a panic button too.

As per a couple of the posts above, it would be interesting to know if the unlocking via RF is working.

Can you try unlocking from the front / rear of the vehicle (out of sight of the drivers door)

 

[wardpaa]

RF works as I can unlock the car from inside of the house without the key having line of sight with the car, or if the key is in my pocket etc.
Infra red works on the drivers side as the remote windows use infra red. If I hold down a button to operate the windows from outside the drivers door, the key has to point at the handle. As soon as you point it away the windows stop; proving IR comms.
I believe the EIM comms work on a rolling code that is sync'd between the key and the immobiliser. There is also another chip in the key fob (that cannot be swapped) that could handle this function and the chip I have swapped operates access only ?
I hope to see a Merc specialist today to see what they say.

 

[Diesel Benz]

RF works as I can unlock the car from inside of the house without the key having line of sight with the car, or if the key is in my pocket etc.
Infra red works on the drivers side as the remote windows use infra red. If I hold down a button to operate the windows from outside the drivers door, the key has to point at the handle. As soon as you point it away the windows stop; proving IR comms.
I believe the EIM comms work on a rolling code that is sync'd between the key and the immobiliser. There is also another chip in the key fob (that cannot be swapped) that could handle this function and the chip I have swapped operates access only ?
I hope to see a Merc specialist today to see what they say.

The key should communicate with EIS too when it requests door locks to be opened. Could it be the power coil broken from the key, the one picking up power from EIS when the key is inserted (the key works without batteries but my understanding is that it does not work at the EIS without the power coil even if it had good batteries)? If it was an ebay key, a loose or bad coild could be the reason it ended up to be sold.

 

[Baron_Samedi]

Good point about the power coil

 

[wardpaa]

Not sure about that as the seller sells one of these keys (2 or 3 button) nearly every day. Don't know where they are coming from but there are all makes and mine was pretty much in new condition. Could be from a lease company of something.

To prove EIS immobiliser does not use RF and the powercoil, try stick a piece of black insulating tape over the end of a good working key fob, just enough to cover the IR lens. My good key does not work when i do this proving that EIS immobilser uses IR, not RF.
Are you saying the powercoil is used during IR use ? can't see how...

 

[Diesel Benz]

To prove EIS immobiliser does not use RF and the powercoil, try stick a piece of black insulating tape over the end of a good working key fob, just enough to cover the IR lens. My good key does not work when i do this proving that EIS immobilser uses IR, not RF.
Are you saying the powercoil is used during IR use ? can't see how...

The key is using IR when communicating with the EIS but the key needs power for that and power comes from the RF field from the EIS (coil) and is captured by the coil at the key.

Try removing batteries from a good key and you see the car starts fine.

 

[wardpaa]

tried swapping the coil and the IR senders but still the same. I will swap the chip back tomorrow and call it quits I think. Guh !

 

[Rumble]

steering lock?

 

[horsesuitedfool]

Did anyone come up with anyone that can swap these over reliably with good results before i start googling surrey electronics specialists!!??

 

[wardpaa]

Horse,
I swapped the chip over OK but I could not for the life of me get the key to turn in the ignition. I used to repair equipment to component level in a previous career, so was able to verify that the key was being energised by the EIS, IR comms were then attempting to communicate with the car, voltages and waveforms the same as a working key etc, so the key was functioning. It would operate remote locking and windows too.
The stumbling block was with the other chip, which could not be swapped from an older style key due it being a different form factor. Its the same model chip though and if it could be adapted would operate the EIS. Space would be an issue though but was tempting.
So I just swapped the first chip back and the old remote worked again.
I spoke to Mercedes and they said that the keys are VIN pre initialised when delivered and then sync'd with your car after first being inserted into your cars EIS. After that they can't be resync'd.
With special key programmers they can be erased, thats why people in China are buying alot of these keys from Ebay and then erasing and coding etc -see youtube. They also sell the equipment if you dare buy it.