Peter Johnson

Ok first, hello all! I have a question. I had my check engine light come on and it took a while to get it checked but it came back with fuel too rich with two codes bank 1&2. It had gone off and come back a few times prior to my getting it read but now I have had a mechanic look at it, He sealed the air intake tubes as one he fallen off and then he reset the cel and the cel was off for half a day then came back. I had another mechanic check it and he thinks the fuel injectors need to be reprogrammed since there is nothing faulty in the reading. All systems read good but I still get the fault codes. I have now put a cleaner in the gas, use shell nitro and changed filters. I refilled last night while check engine light was in and woke up this this morning and started and check engine light was off but came back on when returning home from work. It’s about a 50 mile drive each way. Any ideas, suggestions? There are NO performance issues, no loss of mpg, that’s actually improved. No stalling, no misfires, no hesitations, no egg smell, no gas odors nothing. Seems to run just fine other than those codes..


Edit

MBENZTECH

What codes did you get? There is a difference if the ECU is adding fuel because it's running lean or is removing fuel because it's running rich. The mechanic that told you the injectors needed to be re-programmed..... yeah, stay away from that one!

Peter Johnson

Its too rich bank one and two. Don’t remember codes. I cleaned the sensor MAF and went and got a new one to install. Have new air intake tubes (old were coming apart at connection point) and changed air filters as well as a new gas cap. Going to put it all in and clear code by resetting ecu and then see if codes come back. Problem is it can be so many different things but anything else would have affect on engine performance. But I still drive well, start fine. No hesitation or bad gas odor. MPG hasn’t changed any. If anything it’s gotten better. I haven’t seen one noticeable difference in the way it drives other than this check engine light. It has gone off a few times for a day or so and come back. Once for almost a week. I had the codes deleted after I had it checked out once and the light remained off, cleared emissions and light came back on again the day after.

MBENZTECH

I have seen the air filter housing cause this problem, when is sitting properly on the MAF sensor. It needs to have a perfect seal.

Peter Johnson

Thank you! There was a clip that holds that housing down that was missing so I think it might have been part of the issue. So the sensor may have gotten dirty or damaged. I have cleaned it but not reset ecu yet. After a few drive cycles would it go off on its own if that were the issue? Or do I need to reset ecu to clear codes? I have a new Bosch sensor coming and will replace and reset ecu and see. If that doesn’t work do you have other suggestions? Seems like I may go down the line to eliminate everything but am afraid changing an oxygen sensor isn’t within my skill set and would take it to a mechanic for that...but even so are the codes that generic that in this case it’s a process of elimination?

Mathew Avila

Hey I have the same problem with my own 2009 c300. I just wanted to check up and see if yours got resolved and if so what’d you exactly do. I cleaned my MAF sensor and air flow intake but still the check engine light is on.

Thanks!

Peter Johnson

I cleaned my MAF sensor as well but ended up buying a new Bosch MAF sensor on Amazon and replacing myself. Checking to make sure clamps hold air filter and cleaner box down tight and there’s a nice fit when sitting on the MAF sensor and I’d say after three days of driving the light finally went off and has been off since. It will take a few days or drive cycles for it to reset or for the computer to say things look right.

arikgo

HI i know its an old post but i have the same problem an i wonderd if you managw to solve yours?
was it the maf sensor?
thanks

Peter Johnson

Yup. Got the sensor on Amazon

arikgo

thanks bro , maybe you have the link from amazon ?