Roverron

CL600 has some issues I'm thinking ignition module because misfires are on both sides

P0300
p0301
p0302
P0307
p0308

radride

Wrong part of the forum.

R.K.

benz_addict

The car he's working on is a CL.

Usual suspects include the ignition module, coil packs on the V12

driveability

My 05 CL65 has spit out those codes always on start up cold. It's done it a hand full of times or more in the last 4 months. I just clear them and drive on. The cylinders are firing fine / engine running smooth. Funny things is unlike a misfire on hard throttle the cylinders keep firing. I had a hard throttle code where the cylinder cut off until I cleared the code.
since I moved my ignition module from the engine bay to the front of my grill I haven't had the trouble as much. I guess that just supports the facts its normally a coil or ign module issue. I also think for sure it could be the plugs and boots causing problems as well but the dealers swap out all the parts as a rule. When I worked for GM as a tune up tech I saw a lot of carbon tracking from the plugs to the plug boots causing misfires. The atmosphere around the plugs and boots is harsh for sure and rubber can only Stand so much heat over time. Just my experience's

JPhamily

I had the same problem on my cl55, my ignition module was messed up. Had to get that replaced. You should get it checked out before it becomes a bigger problem. Do you notice that sometimes when you turn the key, it won't start? My machanic told me the problem was because the previous owner of the car messed around with the wiring to install a sound system. That basically messed all the electronics up in the car. I had to get my instrument cluster replaced too because of that.

cjcalo

How many miles on your car and are you on original spark plugs and coil packs? Is your car stock or does it have a tune?

Roverron

the car is a CL600
50K miles
drivers coil pack was replace 2 years ago passengers side was replace 3 years ago
ignition module was replaced last year
original plugs
no file or tune on the car

abiazis

Catalytic converters? since you have changed everything else.......

alx

both banks misfire.

i would say ignition module.

also pull some plugs and read them.

those engines eat plugs like nothing.

i have seen the v12 tt motors needing plugs at 50k miles.

cjcalo

Check to see if you have the updated part number for your coil packs. In general, when the ignition modules completely fail your car won't start at all. When they don't completely fail they cause multiple misfires badly to the point of running like complete crap. It can also cause intermittent starting issues to where your car starts sometimes and it doesn't other times.

Since you have original plugs I would change those first and then see what kind of misfires you get after that. My car also has 50k I just removed the plugs yesterday and they definitely needed to be changed.

When you clear the codes do they come back immediately? Do they come only at wot, or start up or at any time?

Roverron

codes come after driving and its not the same misfires seems to move around. I am thinking ignition module

cjcalo

I had random misfires on both sides. I just changed coil packs and spark plugs today and did about 7 pulls, street driving and idling. No more codes or CEL. Before I couldn't even do a pull I would get CEL about 2 secs after I went wot. I'm not really sure what to say since you have new coil packs and new ignition module. If it were me I'd do like I said before and change spark plugs first.

driveability

I made a good living doing tune up and driveability work for over 20 years and never ran into a cat converter that would set misfire codes. Sure found many that were skewed but a restricted exhaust would present itself with different symptoms way before it would cause a cylinder to misfire. Lack of power, late shifting points on some cars, overheating, and a car which would just not run at high speeds. OH another thing it would be quieter than normal as far as exhaust note. One more, gaskets in front of the converter may fail.

An exhaust system which is restricted is very easy to test. Remove the upstream O2 sensor and place a pressure gage in place. I would snap the throttle hard (4k or so) If you see more than 2 psi its toast. I am sure Mb has a spec.

Bear with me its been some time since I worked in a real shop