cylinder misfire 7-12
MBWorld Fanatic!
Joined: Nov 2010
Posts: 2,605
Likes: 343
From: Welwyn, Herts, UK
2006 S600
Good result; that pretty much mirrors what I did with mine. I never cleared all the misfires until I replaced all the plugs, and cam cover oil leaks also contribute sometimes.
Now, don't forget to make sure the heater intake plenum drain is clear!
Nick
Now, don't forget to make sure the heater intake plenum drain is clear!
Nick
Junior Member
Joined: Mar 2018
Posts: 53
Likes: 2
2003 s600
Have misfire s p0300-p0308 on my 03 s600...coil packs look pretty new an want to say they were replaced by previous owner not long ago...only has 59kmiles on it. While I have not check coil packs and spark plugs in detail, sounds like you fixed yours with a new ignition control? Can you tell me more about how you determined that to be the problem and what it looks like or part number?
Junior Member
Joined: Mar 2018
Posts: 53
Likes: 2
2003 s600
Here is the update.
My very first inclination here was ignition module. After all, all 6 cylinders misfired ALL AT ONCE. I drove less than two miles after it acted up, and put my scanner on it. 7 codes, one for each cyl, and one misc multiple engine misfire. Seemed to me very odd that all 6 would take a dump at once.
Read somewhere that the module rarely causes just one bank to go out. So, started looking at the coils.
Because O'Reilly's was (and still is) back ordered, I bought a used coil pack for $190. It had been tested and working, then sold. The buyer sent it back stating it had misfires on two cylinders, but couldn't say which two. Sounded fishy, so I took a chance even though it was being sold as a core. For $190 figured I could use if for parts if nothing else. Last Sat. I removed driver's side coil pack. Looked absolutely brand new. I am certain it isn't original to the car. The used one I bought had yellow inspection paint on each screw. The one that was in my car did not. Figured, WTH, I want to replace plugs anyway. So, replaced 12 driver's side plugs and installed the used coil pack.
Immediately the CE light came on and I had the same 7 codes as before. Found a used control module on ebay for $300. Installed it today, and it runs perfectly. I am going to leave the used coil pack on that side, and keep my old one for a spare. Like I said, it looks brand new.
One bad note. I normally unhook the battery when replacing electrical parts. Did that today. Unfortunately, I left the trunk lid down far enough, it fell and latched. Had to hook up an auxiliary battery to the lugs under the front carpet to get the trunk open. I was parked under another car, and barely had room to get the pass door open. Took me 45 seconds to change the module and another 45 minutes to get the trunk open.
Anyway, anyone who tells you the module can't just take out one side is simply wrong. I know a couple of you suggested the module, and I would have tried that first, but had already started looking for coils.
Anyway, I am happy with the final ending and will go cancel my order at O'Reilly's in the morning.
Thanks again for all the help. Hopefully this will be of help to someone else. OH, and one summary I read said you need a 12 point 5/16 (or 8mm) socket. Those screws are ETorx, not 12 point.
Over the weekend I will be changing the pass side plugs.
My very first inclination here was ignition module. After all, all 6 cylinders misfired ALL AT ONCE. I drove less than two miles after it acted up, and put my scanner on it. 7 codes, one for each cyl, and one misc multiple engine misfire. Seemed to me very odd that all 6 would take a dump at once.
Read somewhere that the module rarely causes just one bank to go out. So, started looking at the coils.
Because O'Reilly's was (and still is) back ordered, I bought a used coil pack for $190. It had been tested and working, then sold. The buyer sent it back stating it had misfires on two cylinders, but couldn't say which two. Sounded fishy, so I took a chance even though it was being sold as a core. For $190 figured I could use if for parts if nothing else. Last Sat. I removed driver's side coil pack. Looked absolutely brand new. I am certain it isn't original to the car. The used one I bought had yellow inspection paint on each screw. The one that was in my car did not. Figured, WTH, I want to replace plugs anyway. So, replaced 12 driver's side plugs and installed the used coil pack.
Immediately the CE light came on and I had the same 7 codes as before. Found a used control module on ebay for $300. Installed it today, and it runs perfectly. I am going to leave the used coil pack on that side, and keep my old one for a spare. Like I said, it looks brand new.
One bad note. I normally unhook the battery when replacing electrical parts. Did that today. Unfortunately, I left the trunk lid down far enough, it fell and latched. Had to hook up an auxiliary battery to the lugs under the front carpet to get the trunk open. I was parked under another car, and barely had room to get the pass door open. Took me 45 seconds to change the module and another 45 minutes to get the trunk open.
Anyway, anyone who tells you the module can't just take out one side is simply wrong. I know a couple of you suggested the module, and I would have tried that first, but had already started looking for coils.
Anyway, I am happy with the final ending and will go cancel my order at O'Reilly's in the morning.
Thanks again for all the help. Hopefully this will be of help to someone else. OH, and one summary I read said you need a 12 point 5/16 (or 8mm) socket. Those screws are ETorx, not 12 point.
Over the weekend I will be changing the pass side plugs.
Junior Member
Joined: Jun 2018
Posts: 17
Likes: 2
2007 S600
I just got this same issue (misfire 7-12) this weekend and I think mine is due to a prior repaired coil pack. But I have some picture of my piston heads if anyone has a chance to look and opine. Link is https://mbworld.org/forums/s-class-w...ack-plugs.html
Newbie
Joined: Feb 2026
Posts: 1
Likes: 0
Audi
Sounds like quite the shock with the misfires! On your W215, cylinders 7 12 are on the passenger side, so you know which bank to concentrate on. Because its misfiring in multiple cylinders simultaneously, its usually either the coil packs or the coil control module, and you can usually check those with a multimeter for voltage and resistance before replacing either. The car does have dual fuel pumps, but a bank failing independently is less likely, and you’d usually see a separate code for low fuel pressure if that were the situation. One trick that sometimes works is to switch the coil packs from bank to bank and see if the misfire codes shift then you know what you’re looking at without guessing. Have you had a chance to check the voltage on the coils yet or any resistance tests?
Member
Joined: May 2020
Posts: 247
Likes: 57
From: Fort Worth
2005 CL55 AMG || 2005 CL65 AMG || 1989 560SEC
Time kills these as much as heat. If they're 6+ years old and the transformer is older, I'd suspect both. Pretty hard to determine which one is causing a bank misfire. v12icpack.com is a wealth of info on the topic of v12 ignition. He rebuilds the packs to a superior spec, and has a superior voltage transformer that relocates next to the brake booster, so it's not constantly getting cooked on top of the hot engine. Has Youtube videos also.
The mercedes/stock coilpacks aren't really high quality. The random ebay/amazon units from wherever are even worse.
v12icpack guy had to get coils custom made because all the replacements were so trash, lol.
The mercedes/stock coilpacks aren't really high quality. The random ebay/amazon units from wherever are even worse.
v12icpack guy had to get coils custom made because all the replacements were so trash, lol.
Last edited by JustTXn; Feb 19, 2026 at 02:40 PM.
