GEAR 4949680 - Caterpillar

than 5000 ohms. There is a short in the machine harness.Repair: The short circuit is between the voltage sensor signal circuit and either frame ground or the circuit that registered the low resistance measurement.The machine harness is a sealed harness. This harness and the harness connectors are not serviceable. In order to correct a problem with the harness or with a harness connector, the machine harness must be replaced.Refer to the complete machine Electrical System Schematic in order determine the part number for the machine harness.After the new machine harness has been installed, ensure that the problem has been corrected before attempting to operate the machine.STOPTest Step 4. CHECK THE SENSOR POWER SUPPLYThis test step will cause multiple diagnostic codes to be activated by the Generator ECM. Disregard these activated diagnostic codes. These diagnostic codes should reset once the procedure is completed.The key switch and the disconnect switch remain in the OFF position.The machine harness connectors remain disconnected from the Power Inverter, the Generator ECM J2 connector and the Motor ECM J2 connector.
Connect the machine harness connector J2 to the Generator ECM connector. Connect the machine harness connector J2 to the Motor ECM connector.
Ensure that disconnected Power Inverter connector contacts are not making contact with frame ground or any other conducting surfaces.
Turn the disconnect switch to the ON position. Turn the key switch to the ON position. DO NOT START THE ENGINE.
At the disconnected Power Inverter connector, use a multimeter to measure the DC voltage between the ECM +15 VDC power circuit at contact 10 (wire N885-PK) and any of the ECM ground circuits. For example, the ground circuit at contact 38 (wire 234-BK).
At the disconnected Power Inverter connector, use a multimeter to measure the DC voltage between the ECM +15 VDC power circuit at contact 28 (wire N887-PU) and any of the ECM ground circuits. For example, the ground circuit at contact 38 (wire 234-BK).Expected Result:Both of the voltage measurements between the power supply circuits and ground are approximately 15.0 VDC.Results:
OK - The voltage measurements of the ECM +15 VDC power circuits are both approximately +15.0 VDC. The sensor power supplies at the Power Inverter connector are correct. Turn the key switch and the disconnect switch to the OFF position. Proceed to Test Step 5.
NOT OK - The voltage measurements of one or both of the ECM +15 VDC power circuit is well below +15.0 VDC. One or both of the sensor power supply circuits at the Power Inverter connector are not correct.Repair: Both of the ECM +15 VDC power circuits are internally connected in the Generator ECM and in the Power Inverter. If only one of the power supply circuits fail, power will continue to be supplied to the voltage sensors through the other power supply circuit. When possible, the faulty power circuit problem should be investigated and resolved before machine operation can continue.If one of the power supply circuit voltage measurements is not correct and the other power supply circuit voltage measurement is correct, the