- Mercedes Benz E Class How to Replace Ignition Coils
Step by step instructions for do-it-yourself repairs
Multiple check engine codes
So off came the coils and in went new bosch oem plugs. All was fine for about 3 days when as i was getting down on it merge into traffic the engine started to sputter and a check engine light. I nursed it over to autozone and had the codes pulled. Initially, it was just a P0304 misfire on cylinder 4. So I ordered a new coild and replaced. The check engine light didn't go out but it did run better for about a day.
Next day as I was driving it started flashing a check engine light again and started to sputter and hesitate really bad. I went out and bought a OBD2 scanner and pulled multiple codes this time. Ordered the rest of the coils and replaced. This had little to no effect and I still seem to be throwing the same codes. I cleared the codes but they came right back... P0300, P0352, P0353, P0356, P2300 P2309, P0301 and P0304. I'm at a loss. It will still start and run but not very well. I'm thinking Cam Position Sensor, but it doesn't seem like this is easy to diagnose.
Other than that, it seems you've thrown enough money for a few diagnostics at an Indy Benz mechanic. My gut says can sensor given its a 350, but could also be crank sensor. I'd suggest you have a qualified pro look it over.
I actually talked to my indy mechanic. He confirmed what I've heard on here. A bad crank position sensor would keep the car from starting.
The P0300, 0301 and 0304 cyl misfire codes are consequences of the other codes' cause. They will go away when you fix the underlying issue(s) that have the coils so upset.
I doubt your cam sensor has anything to do with it. The codes suggest the coils are not getting voltage, not that they are firing at the wrong time, as a crank or cam sensor problem could cause. It is more likely a power to/from the coils problem.
The most specific codes you are getting are the P2300 and P2309. Those each suggest that those two coils, coil "A" and coil "D", are not getting proper voltage (of the 12V kind). Coils B, C and F are not happy either, but are slightly less specific. I suspect they have the same cause as A and D, but that the ODB2 system can't quite tell.
It ain't the coils that are broken. It is more likely the battery, ignition relays and/or the wires feeding the coils 12V have shorted. A grounding problem affecting all coils is possible. It may also be the engine control module or some aspect of ignition control or monitoring.
Is your battery giving good voltage ? If not, some ignition relay(s) may be on strike for the 12V minimum wage and the coils are missing out.
What should you do? I'd get it to someone who can check the primary circuit voltages, ignition control signals, and look for bad ignition relays and wiring gone bad.
I am not a mechanic and I am simply trying to be as logical as my small brain allows. Good luck!
P0300, Random/multiple cylinder misfire detected
P0301, Cyl 1 misfire detected
P0304 Cyl 4 misfire detected
P0352, Ignition coil "B" primary or secondary circuit malfunction
P0353, ditto for "C"
P0356, ditto for "F"
P2300, Ign coil "A", primary circuit low
P2309, Ign coil "D:, primary circuit low
Yeah I think I'm gonna have to pony up and take it somewhere.... my kung fu is weak in this matter.
I live in the people's republic of Maryland... Closer to Annapolis than DC. Anyone know a good MB tech around the Annapolis area. I have used Mitch Carrs before with good luck but those guys are a bit out of the way for me.
UMMM are the plugs correct part #?
If so. Are coil packs plugged in. I removed all of mine to get at the plugs and had no problems.
Given random plug miss I still suspect CPS. If the CPS is failing it is basically a Hall Effect device with coil of wire/rotating magnet. This means the coil could partially fail before totally failing. I have seen cars run with bad CPS but not drive away. I have also seen them not start and some of them miss.
Given the cps is common to all of the coils and a relatively easy fix I would consider this before digging into more complex items.
THE CPS is a known high frequency fail part. The other items are not.
If it were my car I would install a new CPS and try again. (this of course is based on the Plugs are correct type, gap,install.)
Yes the plugs are YR7MPP33 Bosch OEM. I checked the gap twice... once when I put them in and again when I pulled them to check them.
I also checked that all the coils were seated and plugged in properly. When you say CPS are you talking Crank position sensor or camshaft position sensor?
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I still think that the coils are not getting appropriate signal/voltage. If that is because the management system is bad, poor wiring, or because the CPS is failing, I don't know.
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The CPS IS common to all cylinders.
http://www.rockauto.com/catalog/x,ca...%2Bfor%2BSACHS
The unit was dry when it was pulled so no moisture issues or anything like that.I'm also getting conflicting information. On the one hand, The first place I took it stated that when they were investigating getting a rebuilt unit, most of the vendors said they were starting to get several requests for Mercedes ECMs. On the other hand the dealer I spoke to said that this is the first time he has ever had to look up the part to get info on it.
I'll let you all know if this fixes it once and for all.
The unit was dry when it was pulled so no moisture issues or anything like that.I'm also getting conflicting information. On the one hand, The first place I took it stated that when they were investigating getting a rebuilt unit, most of the vendors said they were starting to get several requests for Mercedes ECMs. On the other hand the dealer I spoke to said that this is the first time he has ever had to look up the part to get info on it.
I'll let you all know if this fixes it once and for all.
they can't sync/unsync as they see fit? Just wondering, because I did something similar on a previous car which was not a mercedes so I can't imagine it's a one and done kind of thing. As in they couldn't repair and reuse your old ecu ever again
I myself think its kind of silly to put a part like this in the engine bay to begin with.... on top of the engine no less where it can cook real well.
WHAT A PITA that was. Cost of ECM,, Locksmith (american truck, who knows who would do MB) Took 4 hrs of computer time for the reprogram.
For MB I don't even want to know the cost. Why can't you buy a VIN matched program loaded at MB direct? You would have to have it installed but the labor is small cost compared to the ECM.
So much for saving a few bucks doing my own work. Lesson learned. Take heed... if its got an electrical connection it may be best to go OEM where Mercedes is concerned.
New ECM doesn't like coils?
Coil resistance, current flow and response time (Q of the coil if I remember my EE ) is really important on solid state computers. Sorry I missed this in the discussion.




