Hey, Im a newb here. I own a 1998 Subaru Impreza Outback Sport. I have replaced the knock sensor twice in the past 6 months. I now have to replace it again because the solid check engine light and th code is telling me that the knock sensor is bad, again. What would be causing my knock sensor to go bad?

http://www.ultimatesubaru.org/forum/topic/116520-knock-sensor-101-and-replacement/

 

That's the best place to start, but a few things:

 

1.)  Where are you buying them?  Brand?

 

2.)  Are you sure you have no other problems?

 

3.)  Is the entire area clear of debris when you installed it (Mine was really dirty and I had to clean that area).

 

4.)  Are you overtightening the bolt?

Both times I've had a mechanic replace it. He got the part both times from O'Reillys. I'll check out the link. Thanks!

Do it yourself next time.  It takes a 12mm socket, an extension, and a ratchet and about 30 minutes (takes a bit finagling the plug around).

 

And these should be under warranty.  If the mechanic is charging you I would question what he is doing.

Edited July 9, 201510 yr by lstevens76