help on codes i'm think ignition module
Thread Starter
Super Member
Joined: Dec 2009
Posts: 848
Likes: 6
From: New Cumberland, PA
ML63
help on codes i'm think ignition module
CL600 has some issues I'm thinking ignition module because misfires are on both sides
P0300
p0301
p0302
P0307
p0308
P0300
p0301
p0302
P0307
p0308
Last edited by Roverron; May 21, 2012 at 01:50 PM.
Senior Member
Joined: Jul 2011
Posts: 386
Likes: 13
Cl65 AMG
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
Member
Joined: Jul 2011
Posts: 204
Likes: 0
From: San Jose, CA
Mercedes CL55
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.
Thread Starter
Super Member
Joined: Dec 2009
Posts: 848
Likes: 6
From: New Cumberland, PA
ML63
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
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
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Member
Joined: Feb 2012
Posts: 144
Likes: 1
2005 CL65
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?
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?
Member
Joined: Feb 2012
Posts: 144
Likes: 1
2005 CL65
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.
Senior Member
Joined: Jul 2011
Posts: 386
Likes: 13
Cl65 AMG
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
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
