Mercedes-Benz Forum banner

New Ignition Control Unit - Different sets of keys

378 Views 9 Replies 7 Participants Last post by  Gumpy
Hi there community - Last July my 1991 560 SEC wouldn't start. The shop I take it to regularly (probably one of the best specialty shops for MB in Dubai) diagnosed a failed ignition control unit. We couldn't find any good 2nd hand control units locally, and anyway the shop didn't recommend going that route, so we ordered a new unit from MB Germany which came with a new key barrel and set of keys (total appx US$ 2,800). Now I have one set of keys to lock and unlock the car, and another to start the car. It's driving me crazy. The shop is proposing to change all the locks again in hopes that fixes it. They found a new set of OEM lock barrels and keys nearby (for doors, trunk, glove box, ignition 1,200 US$). But they are not 100% sure this will be aligned with the new ignition control unit. So... I'm at a loss. It seems silly, but I'm not much of a technical guys... what am I missing here?
1 - 10 of 10 Posts

· Registered
1991 420 SEL
Joined
·
1,110 Posts
You should have given the Mercedes dealer your vin and they would have made you an ignition with same key. the key with a tumbler is not much (around $200)
 

· Registered
1991 560SEC W126
Joined
·
5 Posts
Discussion Starter · #3 ·
So, is that still an option? Keeping everything the same and MB giving me a new ignition barrel? or is it a woulda coulda shoulda?

You should have given the Mercedes dealer your vin and they would have made you an ignition with same key. the key with a tumbler is not much (around $200)
 

· Outstanding Contributor
'17 GLS450, '14 GLK250 "Grandpa's Roadster" Project Car, 350SDL (Sold)
Joined
·
6,028 Posts
Probably a stupid question, but, can you use the original tumbler in the new lock? Or use the original to re-key the new one to match?
 

· Registered
1991 Mercedes-Benz 300SE (W126) In Diamond Blue with champignon interior
Joined
·
323 Posts
I'm pretty sure you'll find the tumbler is the only thing that makes the lock unique.
Curiouser and curiouser.... I had no idea that the ignition lock was coded to the ECU... That is what is being implied right?
 

· Registered
Too many to list
Joined
·
11,844 Posts
I really don’t think the W126 had coded a theft relevant set of parts like the W220 and later
W 140. I bet you could’ve just change the ignition module EZL and that’s all you need to change.
 

· Outstanding Contributor
1989 560SEC, 1989 560SEL, 1995 E420
Joined
·
5,668 Posts
I'm confused. What do you mean by "ignition control unit"? Do you mean where you put the key in to start the car?
 

· Registered
1991 Mercedes-Benz 300SE (W126) In Diamond Blue with champignon interior
Joined
·
323 Posts
I'm confused. What do you mean by "ignition control unit"? Do you mean where you put the key in to start the car?
I'm betting he's talking about the ECU... That was my guess too.
So do we have a definitive answer to whether or not the ignition lock was coded to the ECU & if not then why did the dealership send a new ignition lock & key along with the ECU?
 

· Premium Member
91 420SEL, 72 350SL, 99 S600, 05 F-350, 09 C300, 10 987, 12 GL450 , 87 560SEL ,05 SL600, tractors
Joined
·
640 Posts
Hi there community - Last July my 1991 560 SEC wouldn't start. The shop I take it to regularly (probably one of the best specialty shops for MB in Dubai) diagnosed a failed ignition control unit. We couldn't find any good 2nd hand control units locally, and anyway the shop didn't recommend going that route, so we ordered a new unit from MB Germany which came with a new key barrel and set of keys (total appx US$ 2,800). Now I have one set of keys to lock and unlock the car, and another to start the car. It's driving me crazy. The shop is proposing to change all the locks again in hopes that fixes it. They found a new set of OEM lock barrels and keys nearby (for doors, trunk, glove box, ignition 1,200 US$). But they are not 100% sure this will be aligned with the new ignition control unit. So... I'm at a loss. It seems silly, but I'm not much of a technical guys... what am I missing here?
WEIRD!! Never saw a tumbler coded to an ECU on a W126 like on my W140? Perhaps a model change over fluke? Can you send us a picture of the ingnition tumbler that is on the car so we can see if this is a standard W126 tumbler or the newer ignition lock with the RFI ring?
 
1 - 10 of 10 Posts
Top