Got a bit of head scratcher with water in fuel fault code putting service light on . Code in vehicle ecu is p2264 Sensor circuit open , Looking information on Bosch it’s is linked to fuel heater on fuel filter ( found 25 amp fuse blown on this circuit) fixed no difference The three wire water in fuel sensor isn’t fitted to this vehicle just pushed into blank We got battery voltage earth and around 11 odd volts on third wire . Reg : PF16EYK

In the workshop we have 3 different manufacturer vehicles with a diesel fuel problem. Two have been fuelled with Petrol. I am trying to find out information, however I having difficulty finding the answer. On the high pressure fuel pump at the engine, remove the tank return pipe and insert a pipe to a collection container. Turn on the ignition, the tank pump primes and stops when the pressure reaches about 4-5bar at the fuel supply port of the high pressure pump. Am I right in saying there should be no diesel going back to the tank from the high pressure pump until the engine is cranked? What is the expected resistance of the return valve solenoid / pressure regulator in the high pressure pump? Using Alldata and it is not mentioned on the 3 vehicles.

After the post I put in the WhatsApp group ID had a bad cam signal were it would drop out then come back fine so today I had more time to diagnose it properly so I disconnected the plug to do a grab test to find the nice green stuff after a good clean put back and tested on the scope had it running about 20 mins and not one drop out and no engine mil light on