ENGINE AR 1262417 - Caterpillar

Use this procedure to troubleshoot any suspect problems with the digital sensor supply.Use this procedure to troubleshoot the system when one of the following diagnostic codes is active or easily repeated:
41-03 8 Volt DC Supply short to +batt
41-04 8 Volt DC Supply short to groundThe Electronic Control Module (ECM) creates a regulated voltage of 8.0 0.4 VDC that is supplies to terminal A of the engine coolant level sensor.This sensor is optional equipment.A +8 V diagnostic code is probably caused by a short circuit to ground or a short circuit to another voltage source in the harness. The next likely cause is a problem with a sensor. The least likely cause is a problem with the ECM.
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Schematic for the digital sensor supply
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove electrical power from the ECM.
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ECM connectors (typical example)
(1) J1/P1 ECM connector
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Customer connector (typical example)
(2) P61 Customer connector
Thoroughly inspect connectors (1) and (2). Inspect the connectors for each digital sensor. Refer to Troubleshooting, "Electrical Connectors - Inspect".
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P1 ECM connector
(P1-3) Sensor return
(P1-4) +8 V digital supply
(P1-46) Coolant level
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Terminal locations at the P61 customer connector
(P61-8) +8 V digital supply
(P61-15) Sensor return
(P61-36) Coolant level
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Sensor connector
(Terminal A) +5 V supply
(Terminal B) Sensor return
(Terminal C) Sensor signal
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the digital sensor supply.
Check the allen head screw on the ECM connectors and the customer connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasions and for pinch points from the battery to the ECM. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The connectors and wiring are okay. 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
Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools".
Restore electrical power to the ECM.
Monitor the active diagnostic code screen on Cat ET. Check for an active 41-03 code and an active 41-04 code. Note: Wait at least 30 seconds in order for the diagnostic codes to become active.Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active.Repair: If any of the above codes are logged and the engine is not running properly, refer to Troubleshooting, "Troubleshooting Without a Diagnostic Code".If the engine is running properly at this time, there may be an intermittent problem in a harness that is causing the codes to be logged. Refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - Either the 41-03 or 41-04 diagnostic code is active at