Diesel additive function fault,P1434 and 1435 multiplexed pump fault no coms with additive ecu, checked wiring upto bsi unit and replaced additive tank with new item and filled with new fluid. Using dec3 to reset parameters for levels in egine ecu but cant clear above codes.Live and earth all check ok.Is the pump controlled by the bsi unit?The customer has 3 vans all same age that have had same fault for some time all high mileage vehicles.Has anyone come across this fault?Suspect fault in bsi.

thanks

Colin