CJofMD

Hi all, I need help. My C300 just started misfiring one morning. I had replaced the spark plugs about 6 months ago. The codes that were present were 0912, 1360, 2093, 2353, 0645, 0780, 0653 and 0629. I checked the current data and it was showing only cylinder #4 misfiring. So I replaced the coil and cleared the codes. I started the car and it ran good for a few minutes and then started to misfire again. This time the codes were 0600, 0632, 0640, 0648 and 0656. I was told to replace the rest of the coils and it should fix the issue. So I replaced the rest of the coils and cleared the codes again. The car started and ran great for about an hour and a half (about 30-40 miles) and then it started to misfire badly. I now have codes 0600, 0912, 0629, 0637, 0645, 0653 and 0563. The car only has 78k on it.. I filled it with 93 octane fuel, the alternator is charging at 14.5v, the battery is less than 1 year old and the car hadn't had any issues up until it started misfiring that morning. Please help.

gamma300C

Check this MB Forum link where I was one of the posters..sounds a lot your problem, doesn't it.

https://mbworld.org/forums/c-class-w...dtc-codes.html

CJofMD

Thanks gamma300C. I guess I will be trying the cam sensors first.

gamma300C

If you are a DIYer you can go through these checks. Values are for a Subie but probably the same for any sensor make. Can't paste YouTube link but a Google Search of "check cam/crank sensor " will get you there.

CJofMD

Thanks again. There is some good information here. Do the cam sensors normally go bad on MBs without setting a code for them?

gamma300C

The company line is that an intermittent cam sensor timing error can set off misfire codes but necessarily a P0340 code. This tends to be thrown when the sensor has failed...the car can be hard pressed to start or run when this happens. I believe an intermittent crank sensor will more often set off its specific code with car showing similar Sx's of poor idle, rough rev'ing, power down.

CJofMD

Ok. I've ordered all four of them. Hopefully, I'll have great news to post by the end of the week.

CJofMD

Sorry it's taken so long for me to reply, but it's fixed. It was the O2 sensor. I replaced all four of them and reset all of the adaptive values and it solved the problems. Thanks for your help.