SUPPORT 1549885 - Caterpillar

Test Step 1. CHECK THE HYDRAULIC PUMP DISCHARGE PRESSURENote: This test step requires the installation of a pressure gauge at the tap for the outlet pressure for the main hydraulic pump. Confirm that the pressure gauge is properly installed and that the pressure gauge will display the expected pressure range before the key start switch is turned to the ON position.
After a pressure gauge is installed at the main hydraulic pump pressure tap, start the engine and run the engine at low idle.
Ensure that all the following conditions are in place before proceeding to the next step:
Disable the steering system by not aligning the joystick to the angle of the front wheels.
Disable the steering system by not having the operator in the operator seat.
Move the implement lockout switch to the LOCK position.
Use the Caterpillar Electronic Technician (Cat ET) diagnostic tool in order to check the status of the main hydraulic pump pressure.
Observe the display of the pressure reading that is on the Cat ET status screen. Note the reading on the pressure gauge from the pump outlet. Compare the two sets of readings. Expected Result:The pressure this is observed on the Cat ET status screen and the pressure that is observed on the pressure gauge are approximately the same. However, the pressure reading is above the 7500 kPa (1089 psi) standby pressure limit.Results:
YES - The pressure observed on the status screen and the value displayed on the pressure gauge are approximately the same. However, the pressure is above the 7500 kPa (1089 psi) standby pressure limit. There is a problem with the operation of the main hydraulic pump. Repair: The standby pressure of the main hydraulic pump is above normal. Repeat this test step in order to ensure that all of the listed conditions for testing are correct.If the main hydraulic pump standby pressure is still above normal, refer to the Testing and Adjusting, RENR8482 service manual for more information for troubleshooting the hydraulic pump.STOP
NO - The pressure value displayed on the Cat ET status screen and the value displayed on the pressure gauge are not approximately the same. The Cat ET status screen is indicating a higher value than the pressure indicated on the gauge. There is a problem with the pressure sensor or in the circuit of the pressure sensor. Proceed to Test Step 2.Test Step 2. CHECK THE SENSOR
Turn the key start switch to the OFF position.
Disconnect the machine harness connector from the pressure sensor.
Turn the key start switch to the ON position. Do not start the engine.
Observe the status of the active diagnostic code for the sensor. Expected Result:The active CID 0597 FMI 14 diagnostic code changed to an active CID 0597 FMI 03 diagnostic code after disconnecting the sensor from the machine harness.Results:
YES - The active CID 0597 FMI 14 diagnostic code changed to an active CID 0597 FMI 03 diagnostic code after disconnecting the sensor from the machine harness. The sensor is causing the problem.Repair: Replace the main hydraulic pump discharge pressure