Alright guys I have been having a problem with getting 0304 and 0111 in that order. I just waited for another code to pop up that was related to 0111 shortly after 300 miles or so I rechecked the code and received 0304, 0903, 0111. So I went about and replaced the canister vent control valve.

Reset the codes and 0903 wouldnt clear so I drove like that for a while and then decided to see if I got it connected good enough. Sure enough it wasnt fully connected. Connected it fully and then reset the CEL. Still as of today about 2 months later I can easily just pull the connector off the vent control valve. It does not seem to lock. I can hear it click into place but I can just pull it off without using the clip.

But that code was cleared CEL was gone. Drove 50 miles and received code 0304 and 0111. I just said screw it and drove on it. About 400 miles later I rechecked the codes and received 0304, 0702, 0111.

I read where 0702 could be caused by the plugs so I went and replaced the plugs since they had like 100K on them. Replaced them and reset CEL. 50 miles later CEL back with 0304, 0111. Continue to drive and check them later to see 0304, 0702, 0111. So I just drive it like it is and reset the CEL yesterday and drove 50 miles and today checked codes and got 0304, 0111. I am sure 0702 will come up shortly like it has been.


After I replaced the plugs my mileage went up to 29 MPG. So nothing seems to be affecting my gas mileage but I just want to get rid of this CEL. It is driving me crazy. If anyone has any type of leads as to what I should do please let me know. I do not want to take my car to anyone to get it fixed.

 

0304: Repalce KS.

0702: Your right bank O2 sensor is unhappy for some reason, and it could be a # of items. Since none of the other codes are evident of another problem associated with that code, perhaps it may just be your O2 sensor.

0111: Recheck your EVAP canister/vent valve and make sure it's doing ok. Doesn't sound like it from what you posted. You may have a leak.

 

I have 0304 and 0702 and I plan on resetting the KS to clear 0304. 0702 is a tricky one tho....because it is Catalyst Efficiency Below Threshold Bank 1.

I have been lead to believe that my main cat is not converting the exhaust gas quickly enough....producing a slower and less efficient cat. Instead of the cat converting like -------- it is like ~~~~~~~ producing a weaker flow. I plan on replacing the cat eventually when I get a new y-pipe. I just hope that it is not an 02 sensor.


So I would start by replacing the KS (0304) and inspecting the evap canister/ vent like NmexMAX said (0111). I do not know how to guide you as far as the 0702 goes, I reset my ECU and drove for 1000 miles before it came back...checking weekly and only the KS (0304) was there. Its a screwy code that leaves me confused....I may bring to several dealerships to get their opinions.

 

Well I really hope it isnt my cat. The cat pretty new. It a cattman cat. I get 0702 but my gas mileage stays the same as it has been. That what I cant figure out. A bad O2 would decrease gas mileage. A bad cat would give a smell if it was bad and wouldnt it decrease gas mileage too? I do not see any type of decrease and the code does not come right back after 50 miles like the others do.

I do not want to replace the KS now cause I am sure that isnt a problem. More then likely it being thrown because of the other code. I would like to get rid of the other code before I mess with the KS.

As far as the EVAP goes I dont seem to be getting another code for a problem so I just dont know where to begin with it.

 

Upon further reading....I am really pissed about the 0702 code. I cannot figure out if it is an 02 sensor or if its the main cat. I think I am about ready to bring it to the dealership to diagnose it (if they dont charge outrageous fees). If your cat is relatively new, I would look into your 02 sensors, and find which one is bad, as that would certainly trip the SES light.

 

Don't go to the dealership. They will start from the top, and replace every and anything related to that code until they fix it.


I'd be hoping it was an O2 sensor..