rmistret

Hey Everybody. I recently had the engine light come on my c300 so I pulled out my trusty Actron meter (which I needed to replace the battery in as I had not used it since 2007) and plugged it into the OBD port. Got 2 codes which were almost identical. P2A00 and P2A00(with a small "pd") after the code. The description states "02 Bank 1 Sensor 1 - Range Performance". I looked through the forums and found the codes but no description of what to do. Here they are:

P2A00 - The signal of the oxygen sensor upstream of the catalytic converter of the right cylinder bank is shifted towards 'Lean'.
P2A00 - The signal of the oxygen sensor upstream of the catalytic converter of the right cylinder bank is shifted towards 'Rich'.
P2A00 - Open circuit in right oxygen sensor upstream of TWC [KAT] (lambda control was switched off).

Two questions: Is this an actual issue? and What do I do about it if it is?

Any specifics on where the involved sensor is should I need to replace it would be appreciated. Many thanks!

phister

Your gonna want the o2 sensor before the cat.have you recently done any maintenance to the car? Like new air filter? Sometimes if the filter isn't properly installed it'll let throw a code but it looks like an o2 issue. if your under warranty have them look at it and see if it needs replacing or clear it out and see if the codes come back.

phister

Also you might want to post this in the w204 forum seeing as you have a c300

rmistret

Thanks phister. I'm familiar with reading the codes. How do I remove them to see if they come back. I have not done any maintenance... but need to as its overdue. I am going to change the oil and filters today. Perhaps I should reset the code (once I know how) after the maintenance to see if it returns. Let me know if you or anyone else agrees. Cheers...

mtnman82

If you can't reset the codes with your scanner, you can disconnect the battery for ~10 minutes - BUT if you do that you'll have to go thru the re-sync process (not a terrible ordeal) to sync your windows/sunroof.

phister

depending on your model you should be able to. I have an Actron scanner and it allows me to clear codes. Once the code is pulled up you should be able to hit the back button and it should have a clear code or erase code selection you can do.

rmistret

My scanner won't allow me to clear the codes... I heard that you can pull a fuse. Anyone know which one? Thanks

phister

I don't know if the fuse trick works with our cars. Only way is to disconnect the battery I believe. Or you can find someone that'll clear it for you.