CEL on and off

Hey guys

On Saturday I replaced a knock sensor in my Scooby (the previous one was ok but decided to replace it anyway) then I was driving the same day and all worked fine.
Next day in the morning a CEL came on at the start of the engine- I checked the blink codes and guess what code 22 = knock Sensor.
-so I checked the connection and all seemed to be fine. I started the engine and after a while the CEL has gone.
-Today in the morning the same story = CEL came up on cold engine - after a few km it's gone again.

Do you think the problem is still there or should I just reset ECU? and again to reset it is it enough just to disconnect a battery for a while?

Do a reset first. Did you have the battery disconnected when changing the knock sensor? What youre describing is exactly what they do with a slightly faulty knock sensor. Also is there any chance you over or under-tightened the new sensor?

you might have over tightened as above an cracked the new sensor.

you need to check it and if it is ok, you need to torque it to the right setting.

this is the problem with replacing parts that are not broken, why would you change the sensor if its not giving you trouble.

"if it ant broke, dont fix it" is probably the best saying i have ever heard in the car world

It's not cracked and tightened to 16 lb-ft as it should be

I replaced it as I've been told its worth to replace it in Subarus every so often.

Ill try to reset ecu and see how it goes.

is it not possible that there is detonation occuring when cold....??

It turned out the brand new knock sensor was faulty! I put another one, and it works a dream.

I bought it from http://www.importcarparts.co.uk/ online.. wonder if they can do anything about it now?