ENGINE AR 3046910 - Caterpillar

Illustration 4 g01159881
Sensor connector
(A) Sensor supply
(B) Sensor return
(C) Sensor signal
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and on each of the wires in the pressure sensor connectors.
Check the allen head screw for each of the ECM connectors and the machine connectors for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasions and for pinch points from each of 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. 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 for each of the connectors 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 the electrical power from the ECM.
Disconnect the harness connectors for the following sensors:
Atmospheric pressure sensor
Injector actuation pressure sensor
Intake manifold (boost) pressure sensor
Engine oil pressure sensor
Fuel pressure sensor
Restore the 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 the 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 voltage is correct at the sensor connectors. Proceed to Test Step 3.
Not OK - The voltage is not 5.0 0.2 VDC. The voltage is incorrect.Repair: Refer to the diagnostic functional test Troubleshooting, "5 Volt Engine Pressure Sensor Supply Circuit - Test".STOPTest Step 3. Check for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Restore the electrical power to the ECM.
Monitor the active diagnostic code screen on Cat ET. Look for an active diagnostic code for an engine pressure sensor. 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 diagnostic codes are active.Results:
OK - No diagnostic codes are active for the engine pressure sensors.Repair: The problem seems to be resolved. The problem may have been related to a faulty connection in the harness. Carefully reinspect the connectors and wiring. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - A 03