COUPLING 9T8434 - Caterpillar

Conditions Which Generate This Code:
Illustration 1 g01941579
Connections of the primary shifter and the secondary shifterThis diagnostic code is associated with the sensor for the transmission gear selector. The FMI 03 means that the ECU reads the signal voltage of the position sensor as being too high.The possible causes of this diagnostic code are listed:
Wire K900-YL is shorted to the +battery circuit.
The sensor has failed.
The ECU has failed. This is unlikely.Note: If the machine is shutdown and the diagnostic code was active, the machine will NOT start again until the diagnostic code has been cleared. In order for the machine to start, the sensor must indicate the NEUTRAL position.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 CID 0702 FMI 03 is active before performing this procedure.Note: Use a digital multimeter for the measurements in this procedure.System Response:The results of this diagnostic code are listed:
The machine will not shift.
The transmission will remain in the current gear.
The lockup clutch solenoid will disengage.Test Step 1. CHECK THE SENSOR.
Turn the disconnect switch and the key start switch to the ON position.
Ensure that the diagnostic code is present.
Observe the status of the diagnostic code. Then, disconnect the machine harness from the sensor.Expected Result: If the sensor is not the cause of the diagnostic code, the diagnostic code remains present. If the sensor has failed, the diagnostic code is NO longer present.Results:
OK - The diagnostic code remains present. The sensor has not failed. The machine harness or the ECU may have failed. Proceed to test step 2.
NOT OK - The diagnostic code is no longer present. The machine harness is correct and the ECU is operating properly. The sensor has failed.Repair: Replace the sensor. Verify that the new sensor corrects the problem.STOPTest Step 2. CHECK THE SIGNAL CIRCUIT.
Turn the key start switch and the disconnect switch to the OFF position.
The machine harness remains disconnected from the sensor.
Disconnect the J1 and J2 connector from the ECU.
At the J1 connector for the ECU, measure the resistance from contact J2-67 (wire K900-YL) to all other J1 and J2 contacts.Expected Result:The resistance should be greater than 5000 ohms.Results:
YES - The resistance is greater than 5000 ohms. The harness is correct. Proceed to test step 3.
NO - The resistance is not greater than 5000 ohms for each measurement. There is a short in the harness. The short is in the wire with the low resistance measurement.Repair: Repair the harness or replace the harness.STOPTest Step 3. CHECK THE RETURN CIRCUIT FOR AN OPEN.
The sensor remains disconnected.
The disconnect switch and the key start switch remain in the OFF position.
The machine harness connectors remain disconnected from the ECU.
At the J1 connector for the ECU, measure the resistance between the return contact J2-68 (wire K990-GN) and contact 7 (wire K990-GN) at the sensor. Expected Result:The resistance is less than 5 ohms.Results:
YES - The resistance is less than 5 ohms.