where is knock sensor on C20LET?

[noelboy]

After finally changing over my head gasket, I took it for a spin and the EML was flashing up every now and then.
After about another 20 mins the light was on permanently.
I've flashed out the code and its 23 (Knock Sensor).
Im trying to find where it is to check the plug for it (im hoping its just come loose)?
Also if it isn't the plug any ideas what else it could be?
Cheers

[C4LIBR4]

The knock sensor is on the back of the block, under the inlet and next to the idle control valve, it has a red connector plug on it.

[noelboy]

Cheers mate, im back off out to hopefully find the connector isn't on properly