How To Quickly Check Coil-Packs At Home

Things You'll Need:
Tools to remove engine cover
Proper Socket to fit coil pack bolts
Ohm/Continuity Meter

1
Park your car in a safe place and open the hood.

2
Locate the coil packs in your engine. They are usually on top at each cylinder location.

3
Remove the suspected coil pack bolts. Mark or label it if removing more than one.

4
Unplug the pack's electrical connector and remove the coil pack from the engine. Notice that there are three prong connectors inside the coil-pack socket.

5
Turn on your meter and set it to check the continuity range. Touch one probe to the spark plug terminal inside the boot and the other to the center terminal inside the connector socket end. It should be 0, so no continuity. If it's shows continuity, or any reading above 0, the pack is shorted out.

6
Set your ohmmeter to the 10 ohms range, and touch the outer two terminals inside the coil-pack's socket. You should not get more than 0.5ohms. Anything more the pack should be replaced.

Most Benz engines have now moved to coil on plug. Same applies.

What do you think I was describing?

I thought you were describing M112 style coilpacks that were bolted onto the cambox with HT leads to plugs rather than M272 generation that merely clip over the plug. No HT leads. By definition - coil on plug!

You discuss "coil pack bolts"

Sorry for the confusion in symantics... these are the bolts I was talking about... and yes I was referring to W204 coil-on-plug configuration since this is the W204 C-Class forum.

It is difficult to know what you are talking about when you use incorrect illustrations and parts.

Wayne

Sorry again, but actual pictures are not available, so these are close representations....

No worries. Hopefully most of us won't have the problem. If I do, I will trust the dealer to know what is needed.

Wayne

update from me, the original post on this engine misfire:

today marks 19 days in shop, second service for the same problem. Technicians have put ~ 400 miles on a 3-month old car, after repeated engine component replacements and extended text drives. No ETA on the fix yet.

I'm not interested in lemon law advice. I trust MB service will make good or will make good will.

Dealer's client-service management has been great. I needed an AWD for the snow, and Service rented a dodge through Hertz to make sure I would be driving a safe vehicle in winter weather driving conditions.

I hope hope hope my car, if i get it back, smells like a new car.

Lastly, most importantly, if I get it back, I hope my car doesn't kill me.

Look forward to my next update. I am!

-J

Our condolences. I do hope they can make it right. At this stage, you would think that they could/should have replaced the whole engine. Although I suppose that there are so many engine managment components scattered throughout the car that an engine replacement might not cure the problem. I have never heard of this happening, but you might ask for some extra time/miles on the warranty. Or assurances that M-B will make your car right if these problems surface again.
Thanks for keeping us updated. Information on problems like this are a good thing.
Good luck! Be safe!

Wayne

My truck has thrown a P030x (x being 1 through 8 indicating the cylinder that is misfiring). Chances are the MB is throwing the same/similar code. If so it's usually the COP or the plug itself. I've replaced a few COPs but finally realized it's been my plugs (160K miles on them.) Either way it should be an easy fix for the dealer. Also, for fun you can buy a cheap OBDII to usb cable with s/w to see how your engine is performing even if the check engine light doesn't light. Pretty useful for troubleshooting quirks.

My last update:

Today, 1/25/12, Service fixed an issue they believe to be the roote cause of cylinder 3 misfire: extra/double spring cap with cylinder three.

Service added 600 miles to the car during service and replaced seven engine components before discovering the double spring cap.

After 19 days and 600 miles, the car smells awful and no longer exudes the new car smell &/or leather smell that Mercedes heritage is so proud of (judge you will, yes, i paid for factory premium leather).

There are scratches and grease marks.

The foreman signed my paperwork agreeing that he noticed the same things I described above.

A few days ago, CEO Stephen Cannon received my letter stating my concerns about my safety, initial quality, and damage due to Service driving my vehicle.

Stephen responded with five days, indirectly through my Case Manager. Case Manager's communication lacked substance, accuracy, and willingness to agree to any next steps. This communication channel was the least helpful during the entire process.

I'm hoping MB will do more, and if so I'll let you know. Otherwise, this is my last MB post ever because I quit the MB club, I don't belong here.

bye guys and drive safe

OH - and i promise to show the paperwork to everyone

I'm really sorry to hear about what they did to you. This is the story 9/10 times with dealer service and with all that time and miles the damage to your car is to be expected. It's obviously completely unacceptable. You need to make things right, on principal alone. Start out with complaints to the BBB, attorney general, etc. When that doesn't work, it's time to sue. You can take them to small claims court and sue for the maximum if you don't want to get involved with lawyers.

I hate seeing posts like this. Dealer inability to diagnose & that terrible word "collateral" damage done by techs is unforgiveable. We have every right to expect our vehicles returned by dealers in at least the same condition they received them.

Good luck with resolving this.

600 miles?! You should just try to contact MBUSA, and let them know you don't want the car. That's what I did last time for my 2011 C300. At the end, I got them buy back the car.
I also have similar doubts about the mileage which got put on my car, but it's way less than your. However, I strongly doubt that they took my car for joy ride because there were a period of time my car was checked out without letting me know. The service director at Fletcher Jones Fremont was not very helpful either.
My last C300 was from Africa. I have ordered another 2012 C350 from a different dealer now which is on the way from Germany. I have not totally given up on MB yet. I like the design of C series. But the quality wise, it's a bit hard to tell now.
Hope you can get a satisfied answer from MB.