GASKET 9N5201 - Caterpillar

System Operation Description:Use this procedure to troubleshoot any suspect problems with the following sensors:
Fuel pressure sensor
Engine oil pressure sensor
Turbocharger outlet pressure sensor
Atmospheric pressure sensorThis procedure covers the following open circuit diagnostic codes and short circuit diagnostic codes:
94-03 Fuel Pressure open/short to +batt
94-04 Fuel Pressure short to ground
100-03 Engine Oil Pressure open/short to +batt
100-04 Engine Oil Pressure short to ground
273-03 Turbo Outlet Pressure open/short to +batt
273-04 Turbo Outlet Pressure short to ground
274-03 Atmospheric Pressure open/short to +batt
274-04 Atmospheric Pressure short to groundThe 5 volt sensor supply provides power to all 5 volt sensors. The Electronic Control Module (ECM) supplies 5.0 0.2 VDC to terminal A of each sensor connector. The sensor return 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 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 a problem 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 a -03 diagnostic code 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 OK. If the sensor is disconnected at the sensor connector, the absence of pull-up voltage at the sensor connector indicates a problem in the signal wire. 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 g01174890
Schematic for the engine pressure sensors
Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01174896
Sensor locations
(1) Fuel pressure sensor
(2) Turbocharger outlet pressure sensor
(3) Atmospheric pressure sensor
(4) Engine oil pressure sensor
(5) J2/P2 ECM connector
Thoroughly inspect the connectors that are for pressure sensors (1), (2), (3), and (4). Also, thoroughly inspect ECM connector (5). Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 3 g01174894
Terminal locations at the P2 ECM connector that are for the engine pressure sensors
(P2-2) +5 V sensor supply
(P2-3) Sensor return
(P2-14) Atmospheric pressure
(P2-16) Fuel pressure
(P2-24) Engine oil pressure
(P2-40) Turbocharger outlet pressure
Illustration 4 g01159881
Terminal locations at the sensor connector that are for the engine pressure sensors
(Terminal A) +5 V sensor supply
(Terminal B) Sensor return
(Terminal C) Signal
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the circuit.
Check the allen head screw for each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasion and for pinch points from the pressure sensors back to the ECM. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and