So I apologize for making yet another thread but upon searching I don't find much information.

I found the error code P2259 which I found info on.

The two I don't seem to find much on is C2278 and U1900.

The U1900 sounds like a quick fix, but I don't see anything on C2278. Any possible info on this?

 

Ignore U codes unless you know that you have a problem with an electronic control module. Virtually all OBD2 readers that aren't official Mazda ones will return U codes, but no U code can turn on the CEL.

Don't worry about the C code either, under similar reasons. There isn't even a list of C codes in the dealer documentation. I believe they are classified as "Communications" (vs P = Powertrain, B = Body).

Just deal with the P2259, it's the one causing the CEL.

 

Thank you very much, I'll search for a way of fixing it.

When the guy checked the code he looked at me like it was fucked up beyond belief and asked me if I was ******* it.