It came on while I was driving but the car seems to be driving normally. I think it could be that an O2 sensor went out. Can I take my car to autozone and have them read the code? Anybody know if they can do that?

 

ya you can...or you can buy one of your own and read it...i just had to read mine about 2 days ago and found 2 codes

 

cool. don't feel like driving an hour to the mercedes dealer just for this...

 

Mercedes dealers won't read the codes for free. Autozone and few other auto parts stores will read the codes for free.

 

although i'd say the dealer will still charge you to read the codes themselves if you take to them to be fixed...

 

had autozone check the code and it said "secondary air injection system fault" but then I asked my local mechanic and he said it's not a problem to drive but he would check it out if I wanted. I went home for a while and when I got back in to drive to work, the check engine light was off.... so maybe a sensor was just acting up or something.

 

mayhbe...altough it'll probably go off again...my guess is that what ever is acting up isn't completely broke but maybe is getting stuck open/closed or something...what exactly is the 2ndary air injection system? something around the MAF or something?

 

secondary air injection system consists of the air pump and valves to allow that extra air during the first minute after starting (warm-up period). One of the valves (that allow the extra air) must be sticking. It's not that hard to remove those valves and clean them. Black soot tends to form inside those valves and not allowing the diaphram in those valves to move freely.

 

# 5 is the air pump and #35 and # 41 are the shut off valves.

 

IIRC the C230K uses the supercharger as the pump.

 

Then, I am not sure if that car has the change-over valves I was referring to above...

 

If people would fill in their profile properly we would know what car it is !!!!!!