HOSE AS 3955449 - Caterpillar

check the power supply circuits at the ECM in order to verify correct power output from the ECM. If the power supplies are correct, there is a problem between the ECM and the voltage sensor in the crowbar tray assembly. If the power supply voltages are not present at the ECM contacts, proceed to the "CHECK THE OPERATION OF THE ECM" test step.If the continuity of the sensor signal circuit is not correct, check the cabinet harness between the ECM and the crowbar tray connector. Verify that there is not a problem at the terminal block.Once the problem area is found, repair the involved wires or replace the wires.STOPTest Step 4. CHECK THE SIGNAL CIRCUIT FOR A SHORTThe key start switch and the battery disconnect switch remain in the OFF position.The RVDC1 resistor remains disconnected from the circuit.The crowbar tray low voltage harness connector remains disconnected.The harness connectors remain disconnected from the Motor 1 ECM.
At the Motor 2 ECM, disconnect the harness connectors J1 and J2 from the ECM. Examine the pins and the sockets on the mating connectors. Ensure that the contacts are clean, dry, and in good condition.
At the J2 harness connector for the Motor 1 ECM, measure the resistance between the voltage sensor signal circuit contact J2-1 (wire VDC1) and a good cabinet ground point. Measure the resistance between the signal circuit contact J2-1 and each of the other circuit contacts that are used in the connectors J2 and J1. Each individual resistance measurement should be greater than 5000 ohms. A measurement of less than 5000 ohms indicates a short circuit.
At the J2 harness connector for the Motor 2 ECM, measure the resistance between the voltage sensor signal circuit contact J2-1 (wire VDC1) and a good cabinet ground point. Measure the resistance between the signal circuit contact J2-1 and each of the other circuit contacts that are used in the connectors J2 and J1. Each individual resistance measurement should be greater than 5000 ohms. A measurement of less than 5000 ohms indicates a short circuit.Expected Result:Each of the individual resistance checks is greater that 5000 ohms.Results:
OK - There is not any indication of a voltage sensor signal circuit short to any other circuit or to cabinet ground. Before proceeding to the next step, reconnect all of the ECM harness connectors and the circuit burden resistor. Proceed to the Test Step 5.
NOT OK - One or more of the resistance measurements is less than 5000 volts. There is a short circuit between the two circuits that had the low resistance measurement or a short circuit to cabinet ground.Repair: Check the cabinet harness between the ECM and the crowbar tray connector. Check the involved circuits for worn or damaged insulation.Once the problem area is found, repair the involved wires or replace the wires.STOPTest Step 5. CHECK THE OPERATION OF THE VOLTAGE SENSOR
In order to test the operation of the DC Bus Voltage 1 Sensor, refer to the Testing and Adjusting, "Voltage Sensor - Test" section of this