HOSE AS 3543799 - Caterpillar

Illustration 1 g01008896
Illustration 2 g00735242
Schematic for the Pressure Sensor (Head End for the Lift Cylinder)This diagnostic code is recorded when the ECM for the payload system determines that the signal from the pressure sensor for the head end is outside the allowable range.The possible causes for this diagnostic code are listed:
The pressure sensor has failed.
The circuit for the +battery to the sensor has a intermittent connection.
The return circuit from the sensor has a intermittent connection.
The signal circuit from the sensor has a intermittent connection.Note: The lift control lever should be in the FLOAT position. The ride control (if equipped) should be OFF.Note: Ensure that the diagnostic code is still active.Test Step 1. CHECK THE +BATTERY CIRCUIT
Insert the 7X-1710 Multimeter Probes into the connector of the pressure sensor.
Turn the disconnect switch and the key start switch to the ON position.
Measure the +battery voltage at contact A (wire 138-GN) and contact B (wire 251-BK).Expected Result:The +battery voltage should be between 18 VDC and 24 VDC.Results:
YES - The +battery voltage is between 18 VDC and 24 VDC. The voltage is correct. Proceed to Test Step 2.
NO - The +battery voltage is not between 18 VDC and 24 VDC. The voltage is not correct. There is probably a short or an open in the +battery circuit.Repair: Repair the harness or replace the harness.STOPTest Step 2. CHECK THE FREQUENCY OF THE PRESSURE SENSOR
Turn the key start switch to the OFF position.
Disconnect the harness from the ECM for the payload system.
Install a 8T-0859 Pressure Gauge and the proper Diagnostic Hose on the pressure tap for the sensor. Route the diagnostic hose and the pressure gauge into the cab. Route the diagnostic hose so the hose will clear the lift arms during the test.
Connect a 9U-7330 Digital Multimeter or a 8T-5201 Generator and Counter Signal Group between contact 21 (wire 251-BK) and contact 13 (wire C259-GY) to the connector of the ECM.
Turn the key start switch to the ON position.
At the connector for the ECM, measure the frequency of the pressure sensor for the lift arms with zero pressure at the cylinder.
Raise the lift arms until the pressure on the gauge reads 20700 kPa (3000 psi). When the pressure gauge reads 20700 kPa (3000 psi) observe the frequency displayed on the digital multimeter.Expected Result:The frequency should be approximately 200 20 Hz at a pressure of 0 kPa (0 psi). The frequency should be approximately 800 30 Hz at a pressure of 20700 kPa (3000 psi).Results:
YES - The frequency is approximately 200 20 Hz at a pressure of 0 kPa (0 psi). The frequency is approximately 800 30 Hz at a pressure of 20700 kPa (3000 psi). The ECM has probably failed.Repair: It is unlikely that the ECM has failed. Ensure that the diagnostic code is still active. Exit this procedure and perform this procedure again. If the cause of the failure is not found, replace the ECM. See the Troubleshooting, "Electronic Control Module - Replace" section of this manual.STOP
NO - The frequency is