BOOT 5N4444 - Caterpillar

Illustration 1 g02134097
Connections of the Transmission Oil Temperature Sensor
This diagnostic code is associated with the Transmission Oil Temperature Sensor. The FMI 04 means that the Power Train ECM has detected that the voltage of the sensor circuit is below 0.18 VDC and the resistance of the sensor is less than 18.6 ohms. In addition to monitoring the voltage of the sensor signal, the ECM monitors the resistance of the sensor signal. The ECM associates the resistance value of the sensor circuit with a specific temperature of the transmission oil.The resistance range of the sensor that the ECM will consider valid is 33650 ohms at −40 °C (−40.0 °F) to 18.6 ohms at 150 °C (302.0 °F).Conditions that can cause this diagnostic code to be activated are listed below:
The sensor has failed.
The signal circuit in the machine harness is shorted to a ground source.
The ECM has failed. This situation is unlikely.Test Step 1. CHECK THE RESISTANCE OF THE SENSOR
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the machine harness connector from the sensor.
At the connector for the sensor, measure the resistance between contact 1 and contact 2. Expected Result:The resistance measurement is greater than 18.6 ohms.Results:
OK - The resistance measurement is greater than 18.6 ohms. The resistance of the sensor is correct. Proceed to Test Step 2.
NOT OK - The resistance measurement is less than 18.6 ohms. The sensor has failed.Repair: Replace the transmission oil temperature sensor. Ensure that the new sensor corrects the problem.STOPTest Step 2. CHECK THE SIGNAL CIRCUIT OF THE HARNESSThe sensor remains disconnected from the machine harness. The disconnect switch and the key start switch remain in the OFF position.
Disconnect the J1 and J2 machine harness connectors from the ECM.
At the machine harness connector J1, measure the resistance from the signal circuit at contact J1-29 (wire G460-GN(Green)) to frame ground. Measure the resistance from the signal circuit at contact J1-29 (wire G460-GN(Green)) to all of the other contacts that are used in the J1 and J2 connectors for the ECM. Expected Result:Each resistance measurement is greater than 5000 ohms.Results:
OK - Each resistance measurement is greater than 5000 ohms. The circuit is not shorted in the machine harness. Proceed to Test Step 3.
NOT OK - One or more of the resistance measurements is less than 5000 ohms. The signal circuit for the sensor is shorted to another circuit or to frame ground in the machine harness.Repair: The short is between signal wire G460-GN(Green) and the circuit with the low resistance measurement.Refer to the complete Electrical System Schematic of the machine. Ensure that all connections in the signal circuit for the sensor are clean, secure, and in good condition.For information on testing for short circuits and finding short circuits, refer to Testing and Adjusting, "Wiring Harness (Short Circuit) - Test". Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK THE STATUS OF THE DIAGNOSTIC CODE
Inspect the harness connectors. Clean the contacts of the harness connectors. Check the wires for damage