POINTER A 1P7420 - Caterpillar

Illustration 1 g01318019
Schematic for the Hystat Joystick Control BaseThis diagnostic code is associated with the Hystat Joystick Left/Right Position Sensor. The FMI 03 means that the ECM has determined that the signal voltage of the PWM sensor is above normal.The possible causes of this diagnostic code are listed:
The power supply circuit for the sensor is open.
The return circuit is open.
The signal circuit is open or the sensor is disconnected.
The signal circuit is shorted to the sensor power supply.
The sensor has failed.
The ECM has failed. This is unlikely. Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure and in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure.Note: Ensure that CID 1700 FMI 03 is active before performing this procedure.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear the diagnostic codes when problem has been corrected.System Response:A level 2 warning will be generated. Functionality is lost and the ECM cannot determine desired steering. The machine will not be able to be moved.Test Step 1. CHECK THE DUTY CYCLE OF THE SENSOR SIGNAL
Turn the disconnect switch and the key start switch to the ON position. Do not start the engine.
Use a multimeter that is capable of measuring duty cycle in order to check the duty cycle value of the position sensor. The ECM remains connected to the machine harness. At the machine harness connector for the ECM, insert a 7X-1710 Multimeter Probe in the back of signal contact J2-25 (wire C703-BR) and contact J1-56 (wire J764-BR).
Move the sensor through the full range in order to monitor the minimum and maximum duty cycles of the sensor.Expected Result:With the sensor in the neutral position, the duty cycle should be approximately 50%. The high value should be approximately 90% 5%. The low value should be approximately 10% 5%. Results:
OK - The duty cycle values are in the correct range. The operation of the sensor is correct. Proceed to Test Step 5.
NOT OK - The duty cycle values are not in the correct range or the increment and the decrement of the duty cycle is not stable. Proceed to Test Step 2.Test Step 2. CHECK THE VOLTAGE AT THE SENSOR
The disconnect switch and the key start switch remain in the ON position.
Disconnect the sensor from the machine harness.
At the machine harness connector for the sensor, measure the voltage between contact 1 (wire 709-OR) and contact 2 (wire J764-BR).Expected Result:The voltage measurement is 10 0.5 DCV.Results:
OK - The voltage measurement is 10 0.5 DCV. Proceed to Test Step 3.
NOT OK - The voltage measurement is not 10 0.5 DCV. Repair: There may be an open in the machine harness. Check the fuse for this circuit. Ensure that the