I went through another large puddle in my subaru and the CEL came on with a code 42. Knock sensor. Why? I will clear it outr tommorow morn but if I hit anothr puddle it comes back. Anybody ever heard of this? How can I fix it? New sensor and lots of silicone? Please advise.

I went through another large puddle in my subaru and the CEL came on with a code 42. Knock sensor. Why? I will clear it outr tommorow morn but if I hit anothr puddle it comes back. Anybody ever heard of this? How can I fix it? New sensor and lots of silicone? Please advise.

that's odd...can't help you there. how are things in your area? everyone ok?

My guess is that this is a gen I Legacy (90-94),

as no type or year of vehicle is mentioned.

It does help with diagnosing problems.

 

If so these have a problem where the plastic casing

on the knock sensor body splits due to heat. If this is the case, it is possible water (laden with salt possibly) conducts current to ground and thus trips the CEL.

The KS is easy to remove (drivers side of the throttle body and down on the block, 12mm socket on an 8" extention) You could remove it and see if this is the case. Then seal the crack with silicone.

Hope this helps.

they updated the knock sensor. You can get a new one for about 30 bucks

Thanks Josh. I am going to do that. Would it be safe to cover it in silicone just to be on the cautious side? My Roo sees alot of water.

 

 

Thanks for the input from everone. We are getting back to normal down here. I think everyone has their power back. We were without it for 11 days. Oh the things in life we take for granted. Never again....

Not sure the silicone method would be a permanent fix or not. You could try it I guess.