Engine Pressure Sensor Open Or Short Circuit - Test - Perkins M190C Troubleshooting Manual

146
Troubleshooting Section
Engine Pressure Sensor Open
or Short Circuit - Test
System Operation Description:
Use this procedure under the following
conditions:
Use this procedure if another procedure has directed
you here. Use this procedure if any of the following
diagnostic codes are active:
• 0094-03 Fuel Pressure Sensor voltage above
normal
•
0094-04 Fuel Pressure Sensor voltage below
normal
• 0100-03 Engine Oil Pressure Sensor voltage
above normal
•
0100-04 Engine Oil Pressure Sensor voltage below
normal
• 0100-10 Engine Oil Pressure Sensor abnormal
rate of change
•
1785-03 Intake Manifold Pressure Sensor voltage
above normal
• 1785-04 Intake Manifold Pressure Sensor voltage
below normal
•
1785-10 Intake Manifold Pressure Sensor
abnormal rate of change
• 0127-03 Transmission Oil Pressure Sensor voltage
above normal
•
0127-04 Transmission Oil Pressure Sensor voltage
below normal
• 1797-03 Fuel Rail Pressure Sensor voltage above
normal
•
1797-04 Fuel Rail Pressure Sensor voltage below
normal
The following background information is related
to this procedure:
The troubleshooting procedures for the diagnostic
i04010989
codes of each pressure sensor are identical. The 5
V sensor supply provides power to all 5 V sensors.
The Electronic Control Module (ECM) supplies 5.0 ±
0.2 VDC to terminal "A" of each sensor connector.
The sensor common from the ECM connector goes
to terminal "B" of each sensor connector. The sensor
supply is output short circuit protected. A short circuit
to the battery will not damage the circuit inside the
ECM.
Pull-up Voltage
The ECM continuously outputs a pull-up voltage
on the circuit for the sensor signal wire. The ECM
uses this pull-up voltage in order to detect an open
in the signal circuit. When the ECM detects the
presence of a voltage that is above a threshold on the
signal circuit, the ECM will generate an open circuit
diagnostic code (03) for the sensor.
If the sensor is disconnected at the sensor connector,
the presence of pull-up voltage at the sensor
connector indicates that the wires from the sensor
connector to the ECM are not open or shorted to
ground. If the sensor is disconnected at the sensor
connector, the absence of pull-up voltage at the
sensor connector indicates an open in the signal wire
or a short to ground. If the sensor is disconnected at
the sensor connector and the voltage at the sensor
connector is different from pull-up voltage, the signal
wire is shorted to another wire in the harness.
KENR9126