GDI(Gasoline Direct Injection) ECM calculates controlled variable with the signal from fuel rail pressure sensor to control optimized RPM and rail pressure. ECM sends it to IDB(Injector Drive Box). IDB operates fuel pressure valve according to controlled variable from ECM.
Two high pressure pumps pressurize fuel supplied from low pressure pump. Two fuel rail pressure regulator control fuel rail pressure at 35~150bar according to engine RPM.
When ECM detects open in the FPR control circuit, ECM sets DTC P0090.
Item
Detecting Condition
Possible cause
DTC Strategy
Signal check
Poor connection
Short to ground in control circuit
FPR(B1)
Enable Conditions
B+ 10V ~ 16V
Threshold value
Open
Diagnosis Time
Continuous
MIL On Condition
2 Drive Cycles
Fig.1) Normal waveform of FPR at idle.