So my check engine light came on about two weeks ago. After getting back the diagnostics trouble codes, I had about 5 trouble codes. The dude told me it was nothing serious and I need not worry, that my car will just have less powere than usual. Heres what the diagnostic read:

The MIL is command On.

Emissions-Related Powertrain DTCs, Mode 3:
Electronic Control Unit ID: 01
P0301
Cylinder 1 Misfire Detected
P0302
Cylinder 2 Misfire Detected
P0803
1-4 Upshift (Skip Shift) Solenoid Control Circuit Malfunction
P0410
Sec. AIR Injection System Malfunction
P0300
Random/Multiple Cylinder Misfire Detected

Continuously Monitered System DTCs, Mode 7:
No Diagnostic Trouble Codes recorded


I first bought this car Nov. 1 2007 with 78000 miles. This is my first car I purchased, as well as my first Benz. I admit I had accidentally up shifted a few times when I first got it because I was not used to the sensitive shifter. I do have a mechanic to help me but he's on vacation at the moment; so if anyone can please tell me what these codes mean, and what I need to due.??? Thanks a bunch!

 

You don't state model / engine / year etc.

MIL Malfunction Indicator light = CEL Check Engine Light.
This is ON.

P0301/2 = Misfire. The issue is why?
Gearbox and secondary air are more complex but could be linked.

Not sure what Mode 3 / 7 is but I would cancel codes and see if they return (Immediately or after several days etc).
If you have accidently downshifted then this can cause various issues like temporary misfire but upshifting should be fine.

If codes DO NOT come back then don't worry (at least for now).
If they / CEL come back then try to determine the order of reappearing. You may need to scan the ECU on more than one occasion.

In addition I would also get the vehicle serviced so that you know where you are. e.g. When was the air filter, fuel filter etc last changed?
In addition what condition / colour are the plugs.

I DO NOT believe that we are looking at a MAF problem although 78000 is a pretty typical mileage for this common fault.
The misfire on one bank COULD BE O2 sensor or degrading insulation on the plug leads BUT I DO NOT recommend changing parts on a whim.

Try to gather more information as I have suggested.

If the CEL returns immediately after being reset and everything else is in good order (servicing / plug colour etc) then I would be wanting to know what the O2 sensor reading is on each bank.
I may also swap plug leads from LH to RH bank and vice versa to see if the misfire moves sides.

Stuart