5032455 JOHNSON CUSHION

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Schematic
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P2 ECM connector (P2-15) Intake manifold (boost) pressure sensor (P2-17) Sensor common (P2-28) Engine oil pressure sensor (P2-40) Fuel pressure sensor (P2-57) Atmospheric pressure sensor (P2-72) +5 V Supply
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Typical C18 Sensor locations (1) Intake manifold (boost) pressure sensor (2) Fuel pressure sensor (3) Atmospheric pressure sensor (4) Engine oil pressure sensor
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Sensor connectorTest Step 1. Inspect Electrical Connectors and Wiring
Remove the electrical power from the ECM.
Thoroughly inspect the J1/P1 ECM connector and the J2/P2 ECM connector. Thoroughly inspect the connectors for each analog sensor.Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the sensor connectors that are associated with the active diagnostic code.
Check the ECM connector (allen head screw) for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and wiring for abrasions and for pinch points from the 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 are OK. Proceed to Test Step 5.
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 the electrical power from the ECM.
Disconnect all of the following analog sensors at the sensor connector:
Fuel pressure sensor
Engine oil pressure sensor
Intake manifold (boost) pressure sensor
Atmospheric pressure sensor
Restore the electrical power to the ECM.Note: The original diagnostic code may go away. 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.
Measure the voltage between terminal A (5 V analog supply) and terminal B (sensor return) at the sensor connectors.
Remove the electrical power from the ECM.
Reconnect all sensors.Expected Result:The voltage is 5.0 0.16 VDC.Results:
OK - The voltage is 5.0 0.16 VDC. The voltage is correct. Proceed to Test Step 3.
Not OK - The voltage is not 5.0 0.16 VDC. The voltage is incorrect.Repair: Perform 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. Check and record any active diagnostic codes.Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
Determine if the problem is related to a 03 diagnostic code or a 04 diagnostic code.Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active.Repair: 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 04 diagnostic code is active at this time. Proceed to Test Step 4.
Not OK - A 03 diagnostic code is active at this time. Proceed to Test Step 5.Test Step 4. Disconnect the Suspect Sensor in Order to Create an Open Circuit
Remove the electrical power from the ECM.
Disconnect the sensor connector of the suspect sensor with the active 04 diagnostic code.
Restore the electrical power to the ECM. Wait at least 30 seconds for activation of the diagnostic codes.
Access the "Active Diagnostic Code" screen on Cat ET. Check for an active 03 diagnostic code.
Remove the electrical power from the ECM.Expected Result:A 03 diagnostic code is now active for the suspect sensor.Results:
OK - A 04 diagnostic code was active before disconnecting the sensor. A 03 diagnostic code became active after disconnecting the sensor.Repair: Temporarily connect a new sensor to the harness, but do not install the new sensor in the engine. Verify that there are no active diagnostic codes for the sensor. If there are no active diagnostic codes for the sensor, permanently install the new sensor. Clear any logged diagnostic codes.STOP
Not OK - A 04 diagnostic code is still active for the suspect sensor. There is