CASE 1491482 - Caterpillar

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Typical example
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Location of the ECM connector (1) J1/P1 ECM connectors
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P1 ECM connector (P1-66) Desired fuel (P1-05) Sensor returnTest Step 1. Inspect Electrical Connectors and Wiring
Turn the Engine Control Switch (ECS) to the OFF/RESET position. Turn the main disconnect switch to the OFF position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors in the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and the wiring for abrasion and for pinch points.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 connectors and wiring are OK. Proceed to Test Step 2.
Not OK - The connectors and/or wiring are not OK.Repair: Repair the connectors or wiring and/or replace the connectors or wiring.STOPTest Step 2. Check the Current Input to the Signal Converter
Turn the main disconnect switch to the ON position. Turn the ECS to the STOP position.
Measure the current to the signal converter.Note: Some external governors may only be able to output approximately 150 mA. This should not be seen as a problem with the external governor.Expected Result:The current range is between 0 and 200 mA.Results:
OK - The current is within the correct range. Proceed to Test Step 3.
Not OK - The current is not within the correct range.Repair: Replace the external governor that is supplying the controlling current.STOPTest Step 3. Check the Voltage at the Battery
Turn the ECS to the OFF/RESET mode. Turn the main disconnect switch to the OFF position.
Measure no-load battery voltage at the battery terminals. Refer to Systems Operation/Testing and Adjusting, "Test Tools for the Electrical System" for the proper procedures to check the batteries.
Load test the batteries. Use the 4C-4911 Battery Load Tester. Refer to the Operating Manual, SEHS9249. Refer to Special Instruction, SEHS7633.Expected Result:The voltage is 24 3 VDC.Results:
OK - The voltage measures 24 3 VDC. Proceed to Test Step 4.
Not OK - The voltage is not 24 3 VDC.Repair: The batteries or the alternator are causing the problem. Recharge the batteries or replace the batteries. Verify that the original condition is resolved. Refer to Systems Operation/Testing and Adjusting, "Electrical System".STOPTest Step 4. Check the Voltage at the Signal Converter
Turn the main disconnect switch to the ON position. Turn the ECS to the STOP position.
Connect one probe of the voltmeter to the +Battery terminal at the signal converter.
Connect one probe of the voltmeter to the terminal for the sensor return at the signal converter.Expected Result:The voltage is 24 3 VDC.Results:
OK - The voltage is 24 3 VDC. Proceed to Test Step 5.
Not OK - The voltage is not 24 3 VDC.Repair: Check the wiring