Hi Paul, the advance system works by modulating the solenoid, which in turn controls the hydraulic pressure acting on the advance piston, and therefore the position of the cam ring.

You should check the cam box pressure and the advance soleniod(resistance check) along with the PWM command from the ECU before changing the complete Pump assy.

If after testing the pump needs replacing then it is just plug and play after timing it in the normal mechanical way

Regards mark

PS Hi Kelly, you beat me to the reply whilst typing.