BEARING 2F2872 - Caterpillar

Illustration 3 g02729807
Drive motor and Generator current sensors (4) Motor 2 phase current sensors - left to right: M2BCT, M2ACT, M2CCT (5) Generator phase current sensors - left to right: A3CT, A2CT, A1CT (6) Motor 1 phase current sensors - left to right: M1CCT, M1ACT, M1BCT
Remove the cover (3) from the cabinet compartment that contains the M2ACT sensor.
Use the high voltage meter to measure for DC voltage between each of the motor phase bus bars and each of the Generator phase bus bars. Verify that there is less than 50 VDC between the bus bars. Once the voltage level is verified, continue to the next step.
At the ECM harness connector J2, measure the resistance between the sensor signal (+) contact J2-14 (wire IU2-BK) and all of the other circuit contacts that are used in the J2 harness connector.
At the ECM harness connector J2, measure the resistance between the sensor signal (-) contact J2-18 (wire IU2N-BK) and all of the other circuit contacts that are used in the J2 harness connector.Expected Result:Each resistance measurement between the sensor signal circuits and each of the other circuits in the J2 connector measure greater than 4000 ohms.Results:
OK - The resistance measurements are indicating that the current sensor circuits are not shorted to any other circuit in the ECM J2 connector. Proceed to the Test Step 3.
NOT OK - At least one or more of the resistance measurements is less than 4000 ohms. The low resistance between the circuits is indicating that there is a short circuit between one of the current sensor circuits and another circuit.Repair: Check the connectors in the circuits. Ensure that there is no contamination or damage to the connectors that could cause a short circuit.Check the harness for the J2 connector. Look for areas where the wire insulation for two circuits could be worn or damaged.If a connector problem is not found, replace the shielded twisted pair cable that is used to connect the current sensor signal circuits.STOPTest Step 3. CHECK THE STATUS OF THE DIAGNOSTIC CODE
Inspect the harness wiring connectors that are disconnected. Clean the contacts of the connectors. Check the wires for damage to the insulation that can be caused by excessive heat or chafing.
Reconnect all harness wiring connectors. Make sure that the connectors are fully seated and are fastened. Ensure that the retaining bolts are tightened.
Do not install the cabinet low voltage compartment cover at this time. Install all other cabinet compartment covers. Ensure that all of the covers for the high voltage compartments are installed. Ensure that all of the covers bolts are installed and are tight.
Turn the battery disconnect switch to the ON position. Start the engine.
Determine if the MID 170, CID 2789 FMI 03 diagnostic code is active.Expected Result:The MID 170, CID 2789 FMI 03 diagnostic code is not active.Results:
OK - The MID 170, CID 2789 FMI 03 diagnostic code is no longer active. The problem does not exist at this time.Repair: The initial diagnostic code could have been caused by a momentary