LINK (R.H.) 8S2589 - Caterpillar

System Operation Description:Use this procedure to troubleshoot the electrical system if a problem is suspected with the starting system or if one of the diagnostic codes in Table 1 is active.
Table 1
Diagnostic Codes Table
Description Conditions which Generate this Code System Response
444-5 Start Relay open circuit The Electronic Control Module (ECM) detects an open circuit and/or a short to the +Battery in the start relay. The ECM can only detect this condition when the start relay is not energized. The code is logged.
444-6 Start Relay short to ground The ECM detects a short circuit to ground in the start relay. The ECM can only detect this condition when the start relay is energized. The ECM has the ability to crank the engine when the Engine Control Switch (ECS) is placed in the START position. After the ECS is placed in the START position, the ECM will begin the prelube cycle. When the prelubrication pressure switch opens, the ECM will start the first crank cycle. The crank cycle will continue for the time that is equal to the cycle crank time that has been programmed or the crank cycle will continue until the engine speed reaches the crank terminate speed. If crank terminate speed is not reached before the crank cycle time, the starting motor will deactivate at the end of the crank cycle time.This process will repeat for a programmed amount of times (Total Number of Crank Cycles). If the engine does not start, Caterpillar Electronic Technician (ET) will display "OVERCRANK". The engine control will be in an idle state. The process can be restarted by turning the ECS to the OFF position. Next turn the ECS to the STOP position. Then turn the ECS to the START position. The ECM will send a signal to the starting motor relays after the prelube cycle is complete. The starting motor relays will energize closing the normally open contacts of the relays. Current will flow to the starting motors from the "mag relay breaker". The starting motors will begin to crank the engine.The engine can be manually started by using the manual crank switch.
Illustration 1 g01218696
Typical schematic
Illustration 2 g01218697
P2 ECM connector
(P2-6) Crank relay
(P2-7) Return for the crank relay
Illustration 3 g01234146
Location of ECM connectors
Illustration 4 g01218700
"Connector A"
(Terminal 1) −Battery
(Terminal 8) Return for the crank relay
(Terminal 10) Crank relay
(Terminal 19) +Battery Test Step 1. Inspect Electrical Connectors and Wiring
Remove electrical power from the ECM.
Thoroughly inspect the ECM connectors. Inspect all of the other connectors for the circuit. Refer to Troubleshooting, "Inspecting Electrical Connectors" 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 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 connectors and wiring are