ALTERNATOR GP- 4153784 - Caterpillar

To reduce resistance in the wiring harness, there are two isolated power connections to the ECM. The connections must be complete in order to ensure proper engine operation. There is a constant power supply to the ECM when the engine is shutdown. In order to shut off the power to the ECM, the main power needs to be disconnected.
Illustration 1 g01286135
Typical schematic
Illustration 2 g01286137
P1 ECM connector (P1-52) +Battery (P1-53) +Battery (P1-63) −Battery (P1-65) −Battery (P1-70) Keyswitch
Illustration 3 g01234146
Location of ECM connectorsTest Step 1. Inspect Electrical Connectors and Wiring
Turn the "main disconnect switch (MDS)" to the OFF position.
Thoroughly inspect the ECM connectors J1/P1. Inspect all of the other connectors. Refer to Troubleshooting, "Inspecting Electrical Connectors" for the proper procedure for inspecting system wiring.
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 ECM connector (allen head screw) for the proper torque. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.
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 harness and wiring are 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 are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Battery Voltage
Measure no-load voltage at the battery posts. Refer to Systems Operation/Testing and Adjusting 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 no-load voltage at the batteries is at least 23.5 VDC, and the batteries pass the load test.Results:
OK - The no-load voltage at the batteries is at least 23.5 VDC, and the batteries pass the load test. Proceed to Test Step 3.
Not OK - The no-load voltage at the batteries is less than 23.5 VDC, and/or the batteries fail the load test.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 for information on the charging system.STOPTest Step 3. Check the Voltage at the ECM Connector
Disconnect the J1/P1 ECM connector that is located inside the ADEM box.
Turn the "MDS" to the ON position.
Wiggle the harness during the following test steps in order to find an intermittent condition.
Measure the voltage between P1-52 (Positive Battery) and P1-63 (Negative Battery).
Measure the voltage between P1-53 (Positive Battery) and P1-65 (Negative Battery).
Measure the voltage between P1-70 (Keyswitch) and P1-63 (Negative Battery).Expected Result:The voltage is 1 VDC from the voltage at the battery terminals.Results:
OK - The ECM is receiving the correct voltage.Repair: If an intermittent condition is suspected, refer to Troubleshooting, "Inspecting Electrical Connectors".STOP
Not OK