Code 28.....

[Vitesse_6]

Ok I know what code 28 is, I just am unfamilliar about where to look for issues.
For thoes not in the know a code 28, Its a open or short circuit n the post catalytic converter
So, does this sound electrical or is there a o2 sensor after the cat's?
It says the trouble areas are the sub-oxygen sensor or circuit, ECM or circuit.......HUH?
Where would a good place to start looking, Im not a electrical whiz...so use small words
Thanks

 

[cruiserdan]

Bad #2 O2 sensor (the inboard pre-cat). No post-cat sensors in a 94. I would replace both sensors.

 

[Vitesse_6]

Cool, Thanks I figured with the smell and all the poor milage, I just wanted some proof, I think this is a long time coming, I only found out in the last few day's I was suppose to have a CEL go on for 4 sec. at start up...Mine didnt, Long story short I didnt have a bulb in the socket?!? Ive owned it for 2 years....
Thanks again

EDIT, It must just be that time of year I need to replace them on the M3, However on that I get to replace 4