My check engine light just came on and i got the two codes 0509 - upstream oxygen sensor high voltage (left bank) and 0115 - Fuel injection system lean (right bank). My questions are ...what the hell is a left and right bank? , What can cause the car to run lean? Did one of these codes trigger the other? Which oxygen sensor should i replace? How do i solve the 0115 problem? Will anything happen if i drive it like it is? This maxima has been giving me alot of problems for the amount of maintenance i put into it. Also the car is a 1998 GXE 5spd. Any help is appreciated!

 

Left bank is near the fire wall, right bank is up front. A lean condition indicates a possible clogged fuel injector or intake leak. Check all your vacuum hoses for cracks, run a bottle of Techron fuel injection cleaner and some Marvel Mystery Oil in a tank of gas. Clear the error codes and see what if any codes pop up again.

 

After close inspection of the engine bay today i noticed All 4 of the clips on my air filter box were open. Do you think that could have caused the leak and the CEL to come on for leaness? Also do you know what is mean by upstream or downstream O2S? Thanks.

 

Too much air= lean last time I checked. Right bank is near firewall, left is up front.