if you had heavy steering it is not a problem with a sensor mate as the power steering is not electronically controlled. only the hicas is but it is fed from the same power steering hydraulic pump. i would be checking the power steering fluid level and check if the fan belt is tight etc before checking computer stuff. if the belt is tight (able to push the side in about 10mm,~6mm with gates racing belts) and there is plenty of fluid your pump might have a shot seal etc... i highly doubt it will be a sensor playing up as i said before.