Perkins 1106D Troubleshooting Manual page 122

122
Troubleshooting Section
•
100-10 Engine Oil Pressure Sensor abnormal rate
of change
•
1785-3 Intake Manifold Pressure Sensor voltage
above normal
•
1785-4 Intake Manifold Pressure Sensor voltage
below normal
• 1785-10 Intake Manifold Pressure Sensor
abnormal rate of change
•
1797-3 Fuel Rail Pressure Sensor voltage above
normal
•
1797-4 Fuel Rail Pressure Sensor voltage below
normal
The following background information is related
to this procedure:
The troubleshooting procedures for the diagnostic
codes of each pressure sensor are identical. The
5 volt sensor supply provides power to all 5 Volt
sensors. The Electronic Control Module (ECM)
supplies 5.0 ± 0.2 Volts DC 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 (XXX-3) 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.
This document is printed from SPI². Not for RESALE
KENR6201-01