Got a p1135 so before I order the air/fuel sensor I wanted to reset and see if it comes back. Disconnected the battery for a few hours but when I restarted the car the cel came right back on and I didn't lose my radio presets. I thought this was strange. Every other time I cleared the codes using this method, the cel stayed off for at least a few miles. Any thoughts on this???

 

My advice to you is; invest in an OBD II scanner.They are worth their weight in gold,and pay for them selves quickly.And you correctly/properly clear the ecm.Remember,computers really dont like voltage spikes (hence the disconnecting of the battery) and the only true way to clear the OBD II ecm is through a scanner.

 

there is also a fuse you can pull to reset the ecu, ryan is right in that you should use a obd II tool and it is much better but if you have an issue that you will use it one time for one thing or just dont want to shell out the loot for it there are cheats, here is the fuse you can pull in the blue box