BOOT 1988156 - Caterpillar

Illustration 1 g01181797
Schematic diagram for the electrical power supplyTest Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01183529
Location of the P1 ECM connector (typical left side engine view)
Thoroughly inspect the J1/P1 ECM connector, the battery connections, and the connections to the keyswitch. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 3 g01112632
P1 terminal locations for the electrical power supply (P1-48) +Battery (P1-52) +Battery (P1-53) +Battery (P1-61) −Battery (P1-63) −Battery (P1-65) −Battery (P1-70) Keyswitch
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the electrical power supply.
Check the allen head screw for each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Check the harness and wiring for abrasions and for pinch points from the battery to the ECM. Also, check the harness and wiring for abrasions and for pinch points from the keyswitch to the ECM.Expected Result:All connectors, pins, and sockets are completely inserted and coupled. 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 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 at the ECM
Disconnect the J1/P1 ECM connector.
Measure the voltage between P1-52 (+Battery) and P1-63 (−Battery).
Measure the voltage between P1-48 (+Battery) and P1-61 (−Battery).
Measure the voltage between P1-53 (+Battery) and P1-65 (−Battery).
Turn the keyswitch to the ON position.
Measure the voltage between P1-70 (Keyswitch) and P1-63 (−Battery).Expected Result:The measured voltage is between 11.0 VDC and 13.5 VDC for a 12 volt system and between 22.0 VDC and 27.0 VDC for a 24 volt system with no suspected intermittent problems at this time.Results:
OK - The ECM is receiving the correct voltage. Repair: If an intermittent condition is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - Battery voltage is out of range - Proceed to Test Step 3.
Not OK - Keyswitch voltage out of range - Repair: Trace the wiring for the keyswitch from the ECM through the keyswitch circuit to the batteries. Find the problem and repair the problem. Check the circuit protection for the circuit and for the wiring.Verify that the repairs eliminate the problem.STOPTest Step 3. Check the Condition of the Batteries
Measure the no-load battery voltage at the battery posts.
Load test the batteries. Use the 4C-4911 Battery Load Tester. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 and 12 Volt Lead Acid Batteries" and Special Instruction, SEHS7633, "Battery Test Procedure".Expected Result:The batteries pass the load test. The measured voltage is the minimum specification for a 12V or 24V system.Results:
OK - The batteries are OK.Repair: Check the wiring between the batteries