had new sensor fitted as lights came on everynow and then ,since new sensor was fitted lights came on within 30 seconds all the time.came up on star diagnostic can communication with esp faulty also high pressure return pump circuit open shorted quoted me £1600 for new high pressure return pump is this common fault or could something else be at fault as £1600 is a lot of money if it turns out to be a electrical fault any advice would be grateful thanks.