iv just checked the code as to why engine light has come on and its telling me its the knock sensor.
what exactly does this mean?

 

Had the same thing on mine was just a faulty sensor. I ordered one from the US saved a fortune. UK dealer wanted £117.50 the one from the US was £30 posted
Is yours a V3 STI??
If it is the part number is 22060AA061A
Here's where I got it from Auto Parts Fast at RockAuto just put the part number in.

Bit fiddly to get at to change you have to take the intercooler off to get in.

 

cheers for that mate,would ressetting the ecu not work?

 

not necesarily the sensor thats gone, it could be detecting too much knock, which would give you a code too. see if you can clear the code, if not replace the sensor.

 

Are you sure??
I looked into it with mine and was told that the ECU only shows the code if the sensor isn't sending a signal back to the ECU. If it detects a knock it just tries to reduce it with timing/reduced boost etc not by putting the light on.

Its worth trying to reset the ECU first you never know I tried it with mine but it needed a new sensor.

 

reset the ecu and seems to have done the job

 

I have heard of people that have problems when its wet/damp if so probably a crack in the sensor case. Mine had a split in it.

Hope its ok tho.

 

I'm with rbaz, it means there's a problem with the signal from the knock sensor (ie faulty/loose connection) and not that there is excessive knock..!

Also, I thought the oem knock sensor was the same as the one utilised by a knocklink- Bosch..? If so, you can get them for around £30..