Code 22 - knock sensor - troubleshooting?

[Ihatedomestic]

I've been having an intermitten check engine light since I bought my car and have finally got around to looking into the problem (since it doesn't seem to effect driveability).
So, it's a code 22, for the knock sensor. The manual says to check the wiring and the connections (which I will do sometime today).
I guess my questions are:

1.) Will a bad sensor cause the light to come on?

2.) are these sensors actually known to fail?

3.) Will a knocking event inside the engine cause the light to come on? (I don't have Rob's chip with the knock light feature).

Thanks for any input....

[Speed Stick]

When I first got my car I had this cel 22 whenever the car was washed or when it rained. I ordered a new sensor and installed it which solved my issue. Before I removed it I looked at the knock sensor with a flashlight as you can see it from directly above and noticed it had a crack in it. So whenever it got wet it would screw up. So check to see if its cracked.

[ElectricNipple]

Where exactly is the knock sensor? I know it's somewhere under the IC/TB, but can you check it without taking off the IC? My new Robs 440 is throwing a knocklite so I think my sensor is screwed. Also, where can you buy one? Is it a universal part for Subarus?

[Speed Stick]

Ya you can see it without removing the intercooler. I can't remember exactly where but I believe I looked between the intercooler/iacv/throttle body area. Had to look straight down. I wouldn't be surprised if the turbo legacy 91-94 knock sensors were the same.

[Ihatedomestic]

Does anyone know the part # for the knock sensor for the 20G? (or the North American equivalent...)
I tried to look it up on Opposed Forces, but couldn't find it!

[Speed Stick]

http://forums.jdmvip.com/Knock_Senso...Impreza-2376-t

[ElectricNipple]

http://www.ebay.ca/itm/320545016968?...ht_7319wt_1396

I ordered this one a while back. Of the two different types I could see on eBay this style has the same plug as the one I pulled off my car.

[Rubaru]

just take you knock sensor off grab some brake clean, clean the metal surface than take a wratchet tape some sand papar to the bottom and grind away any debre on the engine itself. put the knock sensor back on and if that doesnt work replace it.

i just replaced mine without cleaning or anything and still had code 22 popping up so after cleaning everything i NEVER got it again. been like 8 months now

[jdmvip]

I would double check your sensor, the issue I've come across is that GC8A-B compared to the C (even though the C has the EJ20G) has some parts which have the same part# but are actually different.

One confirmed example is the ignitor's being different. I know the part# that SpeedStick quoted is correct for a GC8B since that's what I have.

Let us know what you find.

[Ihatedomestic]

Just swapped out my knock sensor....with one of these bad boys:
http://www.ebay.ca/itm/SUBARU-IMPREZ...item4cf8631eb7

I figured that for $30 CDN, you really can't go wrong...but I guess I'll find out how well it will actually hold up.
My old sensor has a very visable crack in the top of the plastic case/housing. I have no idea if this was part of the problem, but that was the only obvious thing I could see. The connector was perfect, the bolt was perfect and the all of the mating metal surfaces on the old sensor were perfect (It's a 1 wire sensor, so it obviously grounds itself on the engine block).
I'll let you guys know if I have any trouble with this new one...