SENSOR ADAPTER 1539625 - Caterpillar

Illustration 1 g01139829
Schematic of the Left Joystick Thumbwheel Modulation Control sensor Note: The sensor is not directly connected to the frame ground. The sensor return connects to the ECM, and the ECM connects the sensor return to frame ground internally.This diagnostic code is associated with the Left Joystick Thumbwheel Modulation Control sensor. An FMI 03 indicates the machine ECM has determined the sensor output signal voltage is above normal. Possible causes for this diagnostic code are:
A failed sensor power supply.
A failed or disconnected sensor.
There is an open wire in the sensor circuit.
The sensor output signal is shorted to +battery.
The machine ECM may have failed, but is unlikely.Note: Poor connections are often the cause of a problem in electrical circuits. Before performing this procedure, inspect all the machine harnesses and connectors involved in the circuit. Make sure to verify that all of the connections in the circuit are clean, secure, and in good condition. Correct any problems found with any of the connections. Verify the diagnostic code CID 1657 FMI 03 is still active, before continuing with this procedure.Note: The following test procedure may create other diagnostic codes. Ignore these created diagnostic codes now, but clear those codes when the original diagnostic code has been corrected. System Response:When this diagnostic code occurs, there is no warning on the monitor. The Left Joystick Thumbwheel Modulation Control function will be inoperative.Test Step 1. CHECK SENSOR POWER.
Turn the disconnect switch and the key start switch to the ON position.
Insert the Multimeter Probe leads into the back of the Left Joystick Thumbwheel Modulation Control sensor connector and measure the voltage between contact 1 (wire M947-OR) and contact 2 (wire M948-BR).Expected Result:The voltage is 12.0 DCV.Results:
YES - The voltage is 12.0 DCV. The voltage is correct. Go to Test Step 2.
NO - The voltage is NOT 12.0 DCV. Repair: Reference the complete Electrical Schematics for the machine and investigate the ECM 12.0 DCV power supply problem. After correcting that problem, check if the diagnostic code CID 1657 FMI 03 is still active. If the CID 1657 FMI 03 code is still active, go to Test Step 2. Test Step 2. CHECK THE SENSOR.
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the machine harness connector from the Left Joystick Thumbwheel Modulation Control sensor.
At the sensor harness connector, insert a jumper wire between the contact for wire M943-YL and the contact for wire M948-BR in the sensor harness connector.
Turn the disconnect switch and the key start switch to the ON position.
Observe the status of the CID 1657 FMI 03 diagnostic code. Expected Result:The CID 1657 FMI 03 code stays active. Results:
YES - The CID 1657 FMI 03 code stays active. The sensor is not the problem. Go to Test Step 3.
NO - The CID 1657 FMI 03 code is no longer active and has been replaced by another CID 1657 related code. The sensor has failed. Repair: Replace the sensor. The new sensor will need to be calibrated. Go to Test Step