E36- P1423, P1421, P0420

[jclaw05]

I ran an OBDII on my '96 328i (92k), and have read most of the posts regarding the above-mentioned codes. My question, however, is how do you kow if the secondary air pump is bad? Upon start, it sounds like it is running. However, how is one sure?

I'd rather replace the valve and the (Bank 1) O2 sensor and avoid having to spend another 250 on the pump (as I need a clutch job). Should I just replace all three? Is having these three fault codes indicative of a failure of all three parts? two? one? none?

Any thoughts.

[Bimmer_Angel]

:dunno: Nevertheless, A Warm Welcome to the Fest :thumbup:

I am sure there will be someone here who can help - these Guys are awesome and friendly [well most of them are:rofl:]

[The White Fox]

I'd go from inexpensive to more expensive - check / replace all (3) air lines first ($10.00 ?), there may be a leak, then the valve and lastly your pump.

[plezops]

I would suggest replacing the air lines, and confirming that there is no water in lines, if there is dry them out, and reset the code. My pump sounded like it was working too but after I replaced it I had no problems. If you do have to replace the secondary air pump refer to this post (http://www.bimmerfest.com/forums/showpost.php?p=3293575&postcount=6) for errors 1421/1423, as for the 1420 error I dont know, hopefully someone else here knows.