The Low Pressure Pump (LPP) supplies 65 psi(4.5 bar) of fuel pressure to the High Pressure Pump (HPP).
Using the internally located Fuel Pressure Regulator Valve (FPR), the HPP will boost the fuel pressure from 580 psi(40 bar) at idle to a maximum of 1958 psi(135 bar).
The Fuel Pressure Sensor (FPS) confirms the fuel pressure and returns the signal to the Powertrain Control Module (PCM).
Fuel pressure during limp-home mode is 65 psi(4.5 bar).
P0091 is set when the Fuel Pressure Regulator Valve (FPR) circuit shorts to ground.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Electrical Check | 1. Short to ground in circuit 2. FPR(Fuel Pressure Regulator) |
Enable Conditions |
•
Battery Voltage: 10V~16V | |
Threshold Value |
•
Control Circuit Voltage: Below 2.2V | |
Diagnostic Time |
•
0.8 Second | |
Mil On Condition |
•
2 Drive Cycles |
RPM | IDLE | 1,500 | 6,300 | Fault |
Fuel Pressure(psi) | 580 | 1305~1450 | 1958 | 65 |
Fuel pressure(bar) | 40 | 90~100 | 135 | 4.5 |
Normal idle state.
When FPR circuit shorts to ground.
