P0303 Engine Code
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Senior Member
Joined: Mar 2015
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2010 E550 4MATIC RENNtech Tune
P0303 Engine Code
This error has happened twice now. It's cylinder 3 misfire detected. Both times it was cylinder 3 so this should be a bit easier to troubleshoot? What do I do? Change the spark plug/coil at position 3? Sorry, not really good with mechanics. Of course I can take it in to be looked at.
My car has been driving jerky lately. I have a feeling this is part of the cause. My car is nearing 60k so they are probably going to recommend that I change all plugs.
My car has been driving jerky lately. I have a feeling this is part of the cause. My car is nearing 60k so they are probably going to recommend that I change all plugs.
MBWorld Fanatic!
Joined: Oct 2010
Posts: 5,141
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From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
This error has happened twice now. It's cylinder 3 misfire detected. Both times it was cylinder 3 so this should be a bit easier to troubleshoot? What do I do? Change the spark plug/coil at position 3? Sorry, not really good with mechanics. Of course I can take it in to be looked at.
My car has been driving jerky lately. I have a feeling this is part of the cause. My car is nearing 60k so they are probably going to recommend that I change all plugs.
My car has been driving jerky lately. I have a feeling this is part of the cause. My car is nearing 60k so they are probably going to recommend that I change all plugs.
An easy troubleshooting trick is to swap the coil from the position 3 with another one. No need to touch the plugs and really they should be good way beyond 60000 miles, but you never know...
Anyway, if you are at all hand-on swap the coils and if the error code follows this then it is a coil problem.
I do not know how the cylinders are numbered so hopefully some other members can shed light to this...
MBWorld Fanatic!
Joined: Dec 2011
Posts: 1,273
Likes: 129
From: Orlando, FL
2015 GL550 4matic
An easy troubleshooting trick is to swap the coil from the position 3 with another one. No need to touch the plugs and really they should be good way beyond 60000 miles, but you never know...
Anyway, if you are at all hand-on swap the coils and if the error code follows this then it is a coil problem.
I do not know how the cylinders are numbered so hopefully some other members can shed light to this...
Anyway, if you are at all hand-on swap the coils and if the error code follows this then it is a coil problem.
I do not know how the cylinders are numbered so hopefully some other members can shed light to this...
Exactly this. Swap the coil on the affected cylinder to another cylinder. Clear the codes, if new code comes up, see what cylinder. If the trouble follows the coil, then replace the coil pack.
I've seen that it's recommended to replace all coil packs at the same time, but considering only 60K miles, I think the one would be enough right now, must have got a dud if this is the problem.
It could also be a damaged plug wire, or other things, but try that first, it's free.
