HEAD 1880199 - Caterpillar

Illustration 1 g02115014
Schematic of the "Right-Hand Joystick Thumbwheel" switchThis diagnostic code is associated with the "Right-Hand Joystick Thumbwheel" switch. The FMI 03 means that the machine ECM has determined that the "PWM (Pulse Width Modulated)" duty cycle signal for the sensor is above normal.The sensor operates at a frequency of approximately 500 hertz. The sensor has an operating duty cycle of 20% to 80%. Some possible causes of the diagnostic code are listed below:
The sensor has failed.
The signal circuit of the sensor is shorted to the +battery circuit.
The energize circuit of the sensor is shorted to the +battery circuit.
The ECM has failed. This is unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes and clear these diagnostic codes when the original diagnostic code has been corrected. Ensure that the diagnostic code of CID 2531 FMI 03 is active before performing this procedure.Test Step 1. CHECK THE THUMB WHEEL SENSOR
Turn the key start switch and the disconnect switch to the OFF position.
Access the three " contact joystick connector" for the "Right Hand joystick Thumb Wheel" and disconnect the sensor from the machine harness.
Turn the disconnect switch and the key start switch to the ON position.
Check the status of the CID 2531 FMI 04 diagnostic code.Expected Result:The CID 2531 FMI 03 diagnostic code is no longer active. A CID 2531 FMI 04 diagnostic code is now active.Results:
YES - The active diagnostic code has changed to a CID 2531 FMI 04 diagnostic code.Repair: The thumb wheel sensor on the "Right-Hand Joystick" has failed. Replace the "Right-Hand Joystick".STOP
NO - The active diagnostic code has not changed. The CID 2531 FMI 03 code is still active. Proceed to Test Step 2.Test Step 2. CHECK THE SIGNAL CIRCUIT OF THE SENSOR FOR A SHORT TO THE +BATTERY CIRCUIT
Turn the key start switch and the disconnect switch to the OFF position.
The thumb wheel sensor remains disconnected from the machine harness. Disconnect the machine harness connectors J-1 and J-2 from the ECM.
At the machine harness connector for the ECM J1, measure the resistance from signal contact J2-41 (wire M965-GN) to all J-1 and J2 contacts that are connected to the +battery.Expected Result:Each resistance measurement is greater than 5000 ohms. Results:
OK - Each resistance measurement is greater than 5000 ohms. The signal circuit in the machine harness is correct. Proceed to Test Step 3.
NOT OK - Each resistance measurement is not greater than 5000 ohms. There is a short in the machine harness. The short is between J2-41 (wire M965-GN) and the circuit that has a low resistance measurement. Repair: Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK THE "ENERGIZE VOLTAGE" AT THE SENSOR
Reconnect machine harness connectors J-1 and J-2 to the ECM. The " thumb wheel position sensor" remains disconnected.
Turn the disconnect switch and the key start switch to the ON position.
At the machine harness connector for the sensor, measure the voltage between contact 1 (wire X800-OR) and contact 1 (wire J764-BR). Expected Result:The voltage measurement should