A few months ago, the wife was driving the wagon and the Service Engine Soon light came on. No issues with drivability, no other symptoms - and the code cleared before I got home to check it. I drove it for a while and didn't think anything of it.
Flash forward to last week... and the service engine soon light comes back on. No drivability issues... other than a slight drop in fuel economy... so I head over to my indy mechanic's house to have him read the codes for me (he usually does it for free - I need to get a reader). The code cleared when I started my car just before leaving for my mechanic. But he was able to pull the code - it came up as:
P0161 - O2 Sensor Heater Circuit Malfunction
After looking through the Bentley manual... I found that it is... more completely:
P0161 O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2) - or the Post Cat O2 sensor coming off cylinders 4-6.
Also listed here: http://forum.e46fanatics.com/showthread.php?t=303141
Considering that the code cleared, we're holding off on replacing the sensor for now. I probably should replace at my earliest convenience.
Since no other codes came up during the scan - I'm thinking the original SES light was related.
Anything I might have missed or overlooked?