RING-BACKUP 1140711 - Caterpillar

System Operation Description:Use this procedure under the following conditions:Use this procedure if any of the following diagnostic codes are active:
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
1797-03 Fuel Rail Pressure Sensor voltage above normal
1797-04 Fuel Rail Pressure Sensor voltage below normalThe following background information is related to this procedure:The troubleshooting procedures for the diagnostic 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 V to terminal "1" of each sensor connector. The sensor common from the ECM connector goes to terminal "2" 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 VoltageThe 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.
Illustration 1 g01800518
Typical example of the schematic for the sensors
Illustration 2 g01458448
Typical view of the pin locations on the P2 connector for the pressure sensors (38) Ground (GND) Intake Manifold Pressure Sensor (39) Ground (GND) Oil Pressure Sensor (40) Ground (GND) Fuel Rail Pressure Sensor (46) Voltage supply (5 V) Intake Manifold Pressure Sensor (47) Voltage supply (5 V) Oil Pressure Sensor (48) Voltage supply (5 V) Fuel Rail Pressure Sensor (51) Signal (SIG) Fuel Rail Pressure Sensor (55) Signal (SIG) Intake Manifold Pressure Sensor (56) Signal (SIG) Oil Pressure Sensor
Illustration 3 g01170309
Fuel rail pressure sensor (1) Voltage supply (Vs) (2) Ground (GND) (3) Signal (SIG)
Illustration 4 g01170310
Intake manifold pressure sensor (1) Voltage Supply (Vs) (2) Ground (GND) (3) Signal (SIG)
Illustration 5 g01170311
Typical example of the oil pressure sensor (1) Voltage Supply (Vs) (2) Ground (GND) (3) Signal (SIG)The troubleshooting procedures for the diagnostic codes of each pressure sensor are identical. The pressure sensors are active sensors. The pressure sensor has three terminals. Active sensors require supply voltage from the ECM. The P2/J2 ECM connector supplies +5 V to terminal 1