PUMP GP-MAIN HYDRAULIC 4778794 - Caterpillar

Illustration 1 g01302403
Schematic diagram for the electrical power supply
Illustration 2 g01120079
Left side view
(1) P61 customer connector
(2) J1/P1 ECM connectors
Illustration 3 g01302468
P1 terminals that are associated with the electrical power supply
(P1-44) Shutdown
(P1-48) +Battery
(P1-52) +Battery
(P1-53) +Battery
(P1-55) +Battery
(P1-61) −Battery
(P1-63) −Battery
(P1-65) −Battery
(P1-69) −Battery
(P1-70) Keyswitch
Illustration 4 g01216338
J61 and P61 terminals that are associated with the electrical power supply
(1) +Battery
(26) Keyswitch
(27) Shutdown
(31) +Battery
(32) +Battery
Table 1
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Check all circuit breakers.
B. Check the battery.
C. Turn the keyswitch to the OFF position.
D. Thoroughly inspect connectors (1) and (2). Inspect the connections for the battery and the connections to the keyswitch. Refer to Troubleshooting, "Electrical Connectors - Inspect", for details.
E. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the electrical power supply.
F. Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect", for the correct torque values.
G. 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.
Electrical Connectors and Wiring
Results: The connectors and wiring are OK. Proceed to Test Step 2.
Results: There is a problem with the connectors 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 coupled.
STOP
2. Check the Battery Voltage at the ECM
A. Disconnect the J1/P1 ECM connector.
B. Turn the keyswitch to the ON position.
C. Measure the voltage between P1-52 (Unswitched Positive Battery) and P1-63 (Negative Battery).
D. Measure the voltage between P1-48 (Unswitched Positive Battery) and P1-61 (Negative Battery).
E. Measure the voltage between P1-53 (Unswitched Positive Battery) and P1-65 (Negative Battery).
F. Measure the voltage between P1-55 (Unswitched Positive Battery) and P1-69 (Negative Battery).
G. Measure the voltage between P1-70 (Keyswitch) and P1-63 (Negative Battery).
The measured voltage is between 11.0 VDC and 13.5 VDC for a 12 V system and between 22.0 VDC and 27.0 VDC for a 24 V system.
Results: The ECM is receiving the correct voltage.
Repair: If an intermittent condition is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".
STOP
Results: Battery voltage is out of range Proceed to Test Step 3.
Results: Keyswitch voltage out of range
Repair: Check the circuit protection for the circuit and for the wiring. Trace the wiring for the keyswitch from the ECM through the keyswitch circuit to the batteries. Find the problem and repair the problem. Verify that the repairs eliminate the problem.
3. Check the Batteries
A. Measure the no-load battery voltage at the battery posts.
B. 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 V Lead Acid Batteries" and Special Instruction, SEHS7633, "Battery Test Procedure".
Minimum specification for a 12V or 24V system
Results: The batteries are OK.
Repair: Check the wiring between the batteries and