5031611 JOHNSON **WASHER, LOCK

Illustration 1 g01455647
Schematic for the engine pressure sensors
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
Illustration 2 g01455624
Sensor locations (typical engine views)
(1) J2/P2 ECM conntector
(2) Fuel pressure sensor
(3) Engine oil pressure sensor
(4) Atmospheric pressure sensor
(5) Intake manifold pressure sensor
(6) Turbocharger #2 outlet pressure sensor
Illustration 3 g01455634
Typical location
(7) Turbocharger inlet air pressure sensor
Thoroughly inspect ECM connectors (1). Also, thoroughly inspect the connectors for each pressure sensor. Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 4 g01455656
P2 terminal locations
(P2-15) Intake manifold pressure
(P2-17) Sensor return
(P2-28) Engine oil pressure
(P2-40) Fuel pressure
(P2-41) Turbocharger outlet pressure (No. 2)
(P2-57) Atmospheric pressure
(P2-72) +5 V sensor supply
Illustration 5 g01455657
P1 terminal locations
(P1-2) +5 sensor supply
(P1-3) Sensor return
(P1-15) Turbocharger inlet pressure
Illustration 6 g01215393
Sensor connector
(Terminal A) +5 V sensor supply
(Terminal B) Sensor return
(Terminal C) Sensor signal
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors and on each of the wires in the pressure sensor connectors.
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 of pinch points.Results:
OK - The harness and wiring appear to be OK. There may be a problem with the harness or a connector. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Supply Voltage at the Sensor Connector
Remove electrical power from the ECM.
Disconnect the harness connectors for the following sensors:
Atmospheric pressure sensor
Engine oil pressure sensor
Fuel pressure sensor
Intake manifold pressure sensor
Restore electrical power to the ECM. Note: The original diagnostic code may not stay active. An open circuit diagnostic code for the sensor supply may become active when all of the sensors are disconnected. Ignore the active codes at this time and continue with this test step.Note: Be sure to wiggle the harness during the following measurements in order to reveal an intermittent condition.
Measure the voltage between terminals A and B at each sensor connector on the engine harness.
Remove electrical power from the ECM.
Connect all of the sensors. Expected Result:Each voltage measurement is 5.0 0.2 VDC.Results:
OK - Each voltage measurement is 5.0 0.2 VDC. The supply voltage is correct at the sensor connectors. Proceed to Test Step 3.
Not OK - At least one voltage measurement is not 5.0 0.2 VDC.Repair: There is a problem with the circuit for the +5 V sensor supply. Refer to Troubleshooting, "5 Volt Engine Pressure Sensor Supply Circuit - Test" for information that is related to troubleshooting the circuit.STOPTest Step 3. Check for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Restore electrical power to the ECM.
Monitor the active diagnostic code screen on Cat ET. Look for an active diagnostic code that is related to one of the engine pressure sensors. Note: Wait at least 30 seconds so that any codes may become active.
Determine if the problem is related to an open circuit diagnostic code (03) or a short circuit diagnostic code (04). Expected Result:No diagnos