SECTION 0651428 - Caterpillar

Transmission Gear Lever Selector Sensor (Switch) - Voltage Above Normal
Illustration 1 g01620380
Schematic of the "Position Sensor (Transmission Shift Lever)"
This diagnostic code is recorded when the ECM reads the signal voltage of the transmission gear lever selector position sensor as being too high.The possible causes of this diagnostic code are listed below:
The power supply circuit or the ground return circuit has failed.
Wire M997-PU(Purple) is shorted to the +battery circuit.
The sensor has failed.
The ECM has failed. ECM failure 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.The results of this diagnostic code are listed below:
The machine will not shift.
The transmission will remain in the current gear.
The lockup clutch solenoid will disengage.Test Step 1. CHECK FOR POWER AT THE SENSOR.
Do not disconnect the harness connector from the sensor.
At the back of the harness connector for the sensor, insert a multimeter probe along contact 1 (wire 165-YL(Yellow)) for the voltage supply.
Turn the key start switch and the disconnect switch to the ON position.
Measure the voltage from supply contact 1 (wire 165-YL(Yellow)) to a frame ground . Also measure the voltage from supply contact 1 (wire 165-YL(Yellow)) to ground return contact 2 (wire J764-BR(Brown)). Do not disconnect the sensor. Expected Result:+Battery voltage is present. Sensor supply range is between 9 VDC and 32 VDC.Results:
OK - Battery voltage is present for both measurements. Proceed to Test Step 2.
NOT OK - Battery voltage is missing between sensor contact 1 and sensor contact 2 only. Sensor ground return circuit is open. Proceed to Test Step 4
NOT OK - Battery voltage is missing for both measurements. The +V power circuit is open.Repair: Replace the 7.5 amp "Hoist" fuse (if blown CID 773 code will also be active). Otherwise, check the harness for a bad connector or a broken wire. Refer to the complete Electrical System Schematic of the machine. Ensure that the connections are clean, tight and in good condition, refer to Testing and Adjusting , "Electrical Connector - Inspect". Repair or replace the harness and verify that the diagnostic code has been cleared. STOPTest Step 2. 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 ECM may have failed. Proceed to test step 3.
NOT OK - The diagnostic code is NO longer present. The machine harness is correct and the ECM is operating properly. The sensor has failed.Repair: Replace the sensor. Verify that the new sensor corrects the problem.STOPTest Step 3. CHECK THE