so I was driving back from dropping my brother off at school today (2 hours each way), and my CEL illuminated. When I got home, I read the codes that it was throwing and came up with 0503 and 0115. 0503 is a malfunctioning rear-bank o2 sensor, and 0115 indicates that the rear-bank o2 is sending a signal to the ECU telling it that the rear bank of cylinders is running too lean. I promptly cleared the codes, and went to work. Since then the CEL has NOT illuminated again. WTF?!?!

now if there really is a problem, do you guys think that the 0115 code was thrown just because the o2 sensor itself is messed up, or could I be legitimatly running lean on the rear bank???

 

If it still hasn't come back yet, I wouldn't worry about it. I reset my CEL tonight just for fun, to see how long it would take to come back. Somewhere between my apartment and my work it came back on, between 10 and 15 minutes.

 

if you reset it and it doesn't come back on in a couple days i wouldn't worry about it. and i'm sure you got the lean code because the sensor is on it's way out. i'd order another one for 66 bucks from coz@ultimatez.com