HOUSING 6G6473 - Caterpillar

Test Step 1. CHECK THE SENSOR
Turn the disconnect switch and the key start switch to the ON position.
Disconnect the harness connector of the machine from the main hydraulic pump discharge pressure sensor. Observe the status of the diagnostic code at the same time. Expected Result:The FMI 04 diagnostic code will remain active if the sensor is not the cause of the problem. If the FMI 04 diagnostic code changes to an active FMI 03 diagnostic code after disconnecting the sensor from the machine harness, then the sensor is shorted internally.Results:
OK. - The FMI 04 diagnostic code remains active. The sensor has not failed. Proceed to Test Step 2.
NOT OK. - The FMI 04 diagnostic code changes to an FMI 03 diagnostic code when the sensor is disconnected. The machine harness and the ECM are operating correctly.Repair: The main hydraulic pump discharge pressure sensor has failed. Replace the sensor. After replacement of the sensor, verify that the operation of the new sensor is correct before operating the machine.STOPTest Step 2. CHECK THE POWER SUPPLY AT THE SENSOR
Turn the disconnect switch and the key start switch to the OFF position.
Do not disconnect the machine harness connector from the sensor.
At the back of the machine harness connector for the main hydraulic pump discharge pressure sensor, insert 7X-1710 Multimeter Probes along contact A (wire 997-OR(Orange)) (supply) and along contact B (wire 998-BR(Brown)) (return).
Turn the disconnect switch and the key start switch to the ON position.
Measure the voltage from contact A to contact B. Expected Result:The voltage measurement is 5.0 .5VDC.Results:
OK. - The voltage measurement is 5.0 .5VDC. The voltage is correct. Proceed to Test Step 4.
NOT OK. - The voltage measurement is less than 5.0 .5VDC. The power supply voltage is not correct. Proceed to Test Step 3.Test Step 3. CHECK THE POWER SUPPLY AT THE ECM
Turn the disconnect switch and the key start switch to the OFF position.
At the connector for the Implement ECM J1, use a 151-6320 Removal Tool to remove the supply wire and the socket at contact J1-11 (wire 997-OR(Orange)) and remove the return wire and the socket (wire 998-BR(Brown)) at contact J1-21. The harness connector remains connected to the ECM.
Turn the disconnect switch and the key start switch to the ON position.
Use the multimeter probes to make contact on the connector pins of the ECM. Measure the voltage at the ECM pins between the contact J1-11 (power supply) and the contact J1-21 (return). Expected Result:The voltage measurement is 5.0 .5VDC.Results:
OK. - The voltage measurement is 5.0 .5VDC. The voltage is correct. the ECM power supply is correct. There is a problem in the machine harness.Repair: The Power supply circuit is not connected or the circuit has a bad connection in the machine harness. Refer to the complete Electrical System Schematic of the machine. Examine all of the connectors that are in the power supply circuit. Verify that the connections are clean, that the connections are secure and that the connections