Ignition Voltage Transformer DIY help.
 

Hi, everyone. I'm about to swap the Ignition Voltage Transformer on my dad's 2006 S65 AMG. Basically, this is the little rectangular metal box in the middle of the engine bay.

It seems very straightforward. BUT-- does anyone know if I need to have the unit programmed at the dealership? Or is it just plug and pray... I mean play.

Any other advice would be appreciated!!!

PS-- This is to hopefully fix an intermittent driverside misfire/sluggishness that has been hard to nail down.

Have you changed the coil packs?

Yes, but misfire still an issue. I think it's the transformer, but I just want to know if I have to program it or not.

Ignition box swop
 

Hi, I changed my CL65's coilpacks because of missfires and still had issues. I then fitted a replacement ignition transformer and it cured the problem. The box was a direct swop and didn't need any reprogramming.
Good luck!

Hey, before you spend even more $$$ on that transfomer...I had a similar misfire (search the forum for my threads).
Even after I replaced both coils and all plugs I still had a random #2 & #7 misfire at startup when warm or if I took her over 4500rpm. I was about to replace the transformer, but on a whim I replaced all the air pressure/temp sensors (one on both air boxes and one above the manifold by the intercooler). Also the downstream air intake sensor in the manifold (ironically I had to remove the voltage transformer to get to it). I also replaced the crank Position sensor (since it misfired when hot at startup) and the coolant temp sensor just for good measure. It cured the misfire problem and is running so much smoother overall!\

I don't know which part it was specifically that cured it, or if it was a combination of all, but I figured the ~$125 I spent on all of those beat the $$$ for the transformer (I don't think they typically go bad).

I think the transformer is Plug and play by the way...but be sure it's firmly grounded (metal to metal) on the bracket with the screws (don't try to use spacers to lift it off the hot engine).

i had the misfire codes, also engine wouldn't start and made a weird noise when trying to start. had it towed. tech checked coils, both good and finally found a short in the ignition transformer. changed it out and all is good. i think it's a pretty common problem.

I had the same issues with misfires. Engine then cold ran ok, but when warm multiple misfires on left cyl. bank. MB changed left coilpack, but problem was first solved when power supply (Ignition Voltage Transformer) was changed.

misfires on 7 and 9
 

My recently aquired 2004 SL600 gets the misfires and shuts down power and sputters at the higher rpm. It will reset each time I shut the engine off. It was initially showing misfires on 1,2,7,8,9 and P0300. I changed out the plugs and fixed some vacuum leaks. It still cuts out and now it just shows misfires on 7 and 9. I cleared the codes and 7 & 9 are still the only misfires with the P0300. Would the transformer be able to reset? Any ideas? Thanks,

driver side ignition coil pack

misfires
 

It was the drivers coil pack. Phoenix Motor Company had them in stock. Thanks.

What are the symptoms of a bad/failed Transformer ?

Typically you'll have one cylinder bank, or possibly both lose all spark. Can be caused by a number of things though. Not many people good at actually diagnosing the cause of ignition system problems on these cars, everyone just guesses at replacing parts. It's particularly difficult because of the way Mercedes has it set up...if the transformer senses too high of current going to a coil pack it shuts down that half of its power output until the ignition is cycled. Which is pretty much exactly what would happen if that half of it was bad. To make it even worse, there are also lots of other reasons the engine computer would/could disable an entire bank of cylinders. So it makes it super difficult to determine if it's the coil's fault, or a breakdown in the plug/coil boot, or the ignition transformer, or another unrelated problem.