HOSE A XT-3 4Y0403 - Caterpillar

Illustration 1 g03610786
Illustration 2 g03608581
The possible causes of this diagnostic code are listed below:
Failed sensor
Incorrect hose connection
Failed water pump
Failed hydraulic motor
Check Hydraulic Hose Connection
Park the machine. Turn key start switch to the off position.
Inspect the main hydraulic hose connection between the piston pump and motor.
Inspect the signal and pilot/servo hose connection between the pump and motor.Note: Step 1.c is important and the most commonly seen issue in the field.
Turn the key start switch to the on position. Start the engine, and let the engine idle.
Select the "cannon" mode on the WDS keypad.
Position the water cannon to spray into a remote location.
Turn on the WDS water pump.
Observe and compare the direction of rotation of the water pump shaft with the direction indicated on the water pump housing.Expected Results: The hoses are connected according to the schematics. The water pump direction of rotation is the same as indicated on the pump housing.Results:OK - Hydraulic hose connection and direction of pump rotation is OK. Proceed to Step 2.Not OK - The pump is turning in the opposite direction.Repair: Reconnect the piston pump and motor hoses according to hydraulic schematics. Check for the error code.STOP.Not OK - The signal and pilot/servo hose connection is not correct.Repair: Reconnect the signal and pilot/servo hose connection according to hydraulic schematics. Check for the error code.STOP.
Check WDS Oil Filter
Park the machine. Turn the key switch to the off position.
Remove the WDS oil filter.
Cut open the filter and check for metal debris.Expected Result: The WDS oil filter is clean.Results:OK - No contaminant-related failure. Proceed to Step 3.Not OK - The filter has excess metal debris. The hydraulic pump or motor has failed.Repair: Replace the WDS hydraulic pump, hydraulic motor and charge pump. Flush the WDS hydraulic system.STOP.
Check Water Pressure Sensor
Park the machine. Turn the key switch to the off position.
Install a 376-4170 Pressure Sensor from the 368-9910 Multi-Tool Group in the water piping close to the WDS water pressure sensor.
Turn the key start switch to the on position. Start engine and let the engine idle.
Select the "cannon" mode on the WDS keypad.
Position the water cannon to a spray into a remote location.
Turn on the WDS water pump.
Observe the water pressure from the diagnostic pressure gauge and from the "Pressure Checks" measure group on the MD3 display.Expected Result: The water pressure at low idle in cannon mode is 414 kPa (60 psi).Results:OK - The measured water pressure is the same as the sensor pressure. Proceed to Step 4.Not OK - Water pressure measured by diagnostic pressure gauge is higher than the WDS sensor by 138 kPa (20 psi). The water pressure sensor has failed.Repair: Replace the water pressure sensor.STOP.
Check Hydraulic Pressure
Park the machine. Turn the key switch to the off position.
Install a 376-4170 Pressure Sensor from the 368-9910 Multi-Tool Group in the suction port of the WDS pump. This port is labeled "Ms". Install a 376-4171 Pressure Sensor from the 368-9910 Multi-Tool Group in the discharge port of the WDS pump. This port is labeled "Mp". The size of these