Fuel pressure monitoring is used to detect the troubles and the fuel leakage in high pressure system.
The ECM determines the rail pressure value as a function of the engine’s operating conditions and controls the fuel pressure regulator to ensure that the rail pressure reaches the required value.
Fuel pressure in the fuel line including the pumps and injector are continuously monitored during engine runing.
If the rail pressure is excessive, the fuel pressure regulator opens and a portion of the fuel is returned from the rail to the fuel tank via a collector line. If the rail pressure is too low, the fuel pressure regulator closes.
The fuel pressure regulator closes. the fuel pressure regulator is installed in the tail end of high pressure accumulator.
In case of the insufficient fuel supply in the fuel line, the engine symptoms will occur a shut down and a starting impossible.
If the fuel pressure monitoring in engine fuel pressure line generates threshold value, the ECM judged this as a fault and DTC is set.
Item
Detecting Condition
Possible Cause
DTC Strategy
? Rationality check
? Faulty RPS
? Faulty FPR
? Faulty ECM
Enable Conditions
? Engine run (above 670 rpm)
Threshold Value
? Rail pressure > 1450 bar (Maximum pressure exceed)
Diagnostic Time
? 0.24 sec.
MIL
Fuel Limit
Fuel Cut
EGR Off
? Yes
? No
Rail Pressure
Engine idle state
Fully acceleration (100%)
220 ~ 320 bar (22 ~ 32 Mpa)
1500 bar (150 Mpa)
Signal Voltage
Below 1.7V
Approx. 4.5V