CAP AS 3657388 - Caterpillar

Illustration 1 g02027440
Right Joystick "Thumbwheel Modulation Control" sensor circuit schematic
This diagnostic code is for the Right Joystick "Thumbwheel Modulation Control" sensor. An FMI 03 diagnostic code indicates the Machine ECM has determined the sensor output signal voltage is above the normal limit. Possible causes of this diagnostic code are listed below:
Failed sensor power supply.
Failed sensor.
Open sensor signal output wire.
Sensor signal output wire shorted to +battery.
Failed Machine ECM, but most unlikely.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes now, but clear those codes after the original diagnostic code has been corrected. Note: Poor connections are often the cause of a problem in electrical circuits. Before performing this procedure, inspect all of the harness connectors involved in the circuit. Verify that all of the connections in the circuit are clean, secure, and in good condition. If a problem is found with any of the connections: correct the problem and verify that diagnostic code CID 1658 FMI 03 is still active, before performing the following procedures. System Response:When this diagnostic code occurs, there is no warning on the monitor. The "thumbwheel" control of the joystick will be inoperative.Test Step 1. VERIFY THE +8 VDCSUPPLY.
Turn the disconnect switch and the key start switch to the "ON" position.
Do not disconnect any of the machine harness connectors at this time.
At the machine harness connector for the Right Joystick "Thumbwheel Modulation Control" sensor, measure voltage from contact 1 (wire E472-GN(Green)) to contact 2 (wire 235-BK(Black)) on the sensor connector. Expected Result:The voltage is 8.0 0.5 VDC. Results:
YES - The voltage is 8.0 0.5 VDC. Go to Test Step 2.
NO - The voltage is not 8.0 0.5 VDC. There is a problem with the +8 VDC power supply.Repair: Refer to the complete electrical schematics for the machine. Investigate the ECM +8 VDC power supply problem.After +8 VDC power supply problem is repaired, check if the 1658 FMI 03 diagnostic code is still active. If the diagnostic code is still active, go to Test Step 2.Test Step 2. CHECK THE SENSOR, THE ECM, AND THE MACHINE HARNESS.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connector from the Thumbwheel Modulation Control sensor.
In the harness connector for the sensor, place a jumper wire between the contact for terminal 3 (wire E473-GY(Grey)) and the contact for terminal 2 (wire 235-BK(Black)) in the sensor connector.
Turn the key start switch and the disconnect switch to the ON position.
Observe the status of the CID 1658 FMI 03 diagnostic code. Expected Result:The CID 1658 FMI 03 diagnostic code remains active. Results:
YES - The CID 1658 FMI 03 code remains active. The sensor is not the cause of the problem. Go to Test Step 3.
NO - The CID 1658 FMI 03 diagnostic code is no longer active. The diagnostic code has been replaced by an active CID 1658 with a different FMI code. The sensor has failed. Repair: Replace the sensor.Go to Test Step 5.Test Step 3. CHECK