Perkins NJ Series Troubleshooting Manual page 152

152 SENR9982-01
Troubleshooting Section
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.
g01188154
Illustration 53
Typical example of the schematic for the sensors