METER GROUP 4N3304 - 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
Code and Description Conditions which Generate this Code System Response
444-5 Starter Motor Relay current below normal 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 Starter Motor Relay current above normal The ECM detects a short circuit to ground in the start relay. The ECM can only detect this condition when the start relay is not energized. The ECM has the ability to crank the engine when the circuit for the start/run/stop switch is activated. 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 cycle crank time, the starting motor will deactivate for a time that is equal to the cycle crank time.This process will repeat for a programmed amount of times (Total Number of Crank Cycles). If the engine does not start the starter mode on the Caterpillar Electronic Technician (ET) will display "OVERCRANK". The engine control will be in an idle state.The engine can be started manually by using the manual crank switch.
Illustration 1 g01211167
Typical schematic
Illustration 2 g01211168
P2 ECM connector
(P2-6) Crank relay
(P2-7) Return for the crank relay
Illustration 3 g01211169
Customer connector
(Terminal 12) Crank relay
(Terminal 5) Return for the crank relay 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 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 for Active Diagnostic Codes for the Start Relay
Connect Cat ET to the service tool connector.
Restore electrical power to the ECM.
Turn the start/run/stop switch to the START position.
Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes for the start relay. Note: Wait at least 30 seconds in