Fuel Rail Pressure Sensor

FUEL RAIL PRESSURE SENSOR CHECK OPERATION

DTCs	P0192 (low input), P0193 (high input)
Monitor Execution	Continuous
Monitor Sequence	None
Sensors OK	Not Applicable
Monitoring Duration	8 seconds to register a malfunction

TYPICAL FRP SENSOR CHECK MALFUNCTION THRESHOLDS

Voltage < 0.049 volts or voltage > 4.88 volts

FUEL RAIL PRESSURE SENSOR TRANSFER FUNCTION

FRP volts = [ Vref * (4 * Fuel Pressure / 70) + 0.50 ] / 5.00
Volts	A/D counts in PCM	Pressure, psi
4.85	993	76.125
4.50	922	70
1.00	820	61.25
3.50	717	52.5
3.00	614	43.75
2.50	512	35
2.00	410	26.25
1.50	307	17.5
1.00	205	8.75
0.50	102	0
0.15	31	-6.125

The FRP range/performance test checks to make sure that fuel rail pressure can be properly controlled by the electronic returnless fuel system. The FPS sensor is also checked for in-range failures that can be caused by loss of Vref to the sensor. Note that the FRP is referenced to manifold vacuum (via a hose) while the fuel rail pressure sensor is not referenced to manifold vacuum. It uses gage pressure. As a result, a mechanical gage in the fuel rail will display a different pressure than the FPR PID on a scan tool. The scan tool PID will read higher because of manifold vacuum.

FRP RANGE/PERFORMANCE CHECK OPERATION

DTCs	P0191 (FRP range/performance), P1090 (stuck in range)
Monitor Execution	Continuous
Monitor Sequence	None
Sensors OK	FRP
Monitoring Duration	8 seconds to register a malfunction

TYPICAL FRP SENSOR RANGE/PERFORMANCE CHECK ENTRY CONDITIONS

Entry Condition	Minimum	Maximum
Demand pressure reasonable	35 psig	60 psig
Fuel Level	15%

TYPICAL FRP RANGE/PERFORMANCE CHECK MALFUNCTION THRESHOLDS

Fuel pressure error (demand - actual pressure) > 20 psig

TYPICAL FRP SENSOR STUCK CHECK ENTRY CONDITIONS

Entry Condition	Minimum	Maximum
FRP sensor input	0 psig	46 psig
FRP input not moving		1 psig/sec

TYPICAL FRP STUCK CHECK MALFUNCTION THRESHOLDS

Fuel pressure error (demand - actual pressure) > 5 psig