Can you help guide me in the diagnosis of this non start Fiesta? It arrived on a tow truck and was recovered from the motorway hard shoulder.
I charged the battery and read the codes with my DEC. Six codes were present: P0087 Fuel pressure, P0116 Engine coolant temp sensor, P0571 Brake switch, U0155 No instrument panel comms, U2510 CAN,Invalid data for vehicle security and finaly P0002 Fuel volume regulator control circuit.
The last of the codes (P0002) fuel volume control circuit is the only reoccurring code after cranking.
Having established that the engine would run briefly with a squirt of brake cleaner I have spent time checking a fuel sample which I am happy with and testing the fuel rail pressure sensor output on the scope. There is no fuel pressure in the rail on cranking.
I can see no problem with the wiring or connections between ECU and either the fuel volume solenoid or pressure reg. I have good feeds to both and patterns to suggest the ECU is in control.
The way I understand this system is the ECU has control of both the pressure in the rail by way of the pressure regulator(short fat solenoid) and the volume of fuel via the volume solenoid (longer thinner solenoid). I was thinking the volume control was a way of reducing pumping losses like third piston cut off on Bosch Peugeot pumps. To remove excess work on the pump when it’s not needed. Correct me if I’m wrong.
I have substituted the volume control solenoid. I would like to know what steps you would take next. Is there a way of closing the regulator and opening the volume solenoid to prove that the pump still pumps? The pump is made by Siemens.
So presumably when I crank the engine the ECU closes the reg and after a bit of cranking the ECU then recognises the low pressure signal and stores P0002 volume reg circuit ? That does not sound correct to me. Why not P0087 “fuel rail pressure”?
It seems unlikely to me that the pump has failed whilst in the fast lane despite 100000 miles and eleven years of use. Is it more likely the pressure sensor has failed? Could I have an ECU fault?
Like all of us I would like be accurate in my diagnosis without replacing parts unnecessarily. Removing the pump for testing would be a big job too. Short of information so your help as ever welcome.
Thanks
Christopher.