error code 22 knock sensor help please

hi all,

recently my car started bringing up the check engine light randomly staying on for a short period of time then going back off

now on most occasions the car would hesitate under load just before it came on then it would light up and eventually go back off 

i done the diagnostic thing with the plugs and it came up with code 22 only 

any way i got a knock sensor from east sussex subaru spares and it seemed fine no damage to it but it had a wire coming straight from the sensor were as the 1 on mine had a second plug at the sensor end though the plug that fitted to harness was the same and the sensor head was the same 

anyway fitted it and the check engine light was on constant not going off at all and also hesitant under load yet again but now constant 

i havnt reset the ecu yet could doing this clear the cel or would that happen anyway after changine the sensor ?

thanks for any help info

Take live off battery for a while, i ledt mine off over night and connected it back up and it was fine.
Your car will still be in limp mode as it stores the code til its reset

cool mate ive disconnected the full battery over night wil that be ok ?

I used to do it this way as it does it instantly (sort of) 

Ensure engine is at normal operating temperature, turn engine off

Locate the two ECU connectors, located under the steering column and consist of a black plastic male and female connector, and a green male female connector

With the ignition OFF connect black to black and green to green.

Turn on ignition, do not start the engine, depress the accelerator pedal to full throttle, then return it to the half-throttle position and hold for a few seconds, and then release

Engine Check lamp turns on

Start engine and then drive for at least one minute, keeping road speed above 11 Km/h.

ECU is now re-set.

At this point the check engine light should start to flash the all clear signal (steady 1/2 second interval flashes). If the check engine light does not flash, or indicates some other sequence, there is a fault present in the system, and should be professionally checked for necessary repairs.

Stop the car and turn off the engine.

Disconnect the black and green connectors.

Job done 

done mate and made no difference whatsoever still coming up with code22 and still has a now constant cel

ive ordered a brand new genuine knock sensor now and just have to see if that 1 works if not then there is a problem with the wiring between the sensor and the ecu richard henry motorsport seem to think its that and its a common thing with ver5-6 imprezas

Give drew a ring on 07843421838
Or Andy Kindon on 07734453469

One of them two guys will be able to help you out

Get a multi meter out and test the wiring, not too hard to do.