TUBE ASSEM. 8K5577 - Caterpillar

Illustration 1 g02650056
Schematic of the transmission oil temperature sensor
Table 1
SENSOR TEMERATURE RANGE     TEMP     OHMS    
HIGH    
150° C (302° F)     18    
MID POINT    
95° C (203° F)     80    
LOW    
−40° C (−40° F)     34000    Note: Results will vary due to sensor temperature.This diagnostic code is recorded when the ECM reads the signal voltage of the transmission oil temperature sensor and the voltage is too high.The operating range for the output voltage of the sensor is approximately 0.5 VDC to 5 VDC.The possible causes of this diagnostic code are listed here:
The sensor has failed.
The return circuit of the sensor is open in the machine harness.
The signal circuit in the machine harness is shorted to a source of positive voltage.
The signal circuit in the machine harness is open or the sensor is disconnected.
The ECM has failed. This condition is unlikely. Test Step 1. CHECK THE SENSOR
Turn the disconnect switch and the key start switch to the ON position.
Disconnect the machine harness connector from the sensor.
At the sensor connector, measure the resistance between the signal contact 1 (wire K977-PK) and the return contact 2 (wire C216-BK).Expected Result:The resistance is between 18 ohms and 34000 ohms.Results:
NOT OK - The resistance is NOT between 18 ohms and 34000 ohms.Repair: Replace the sensor.STOP
OK - The resistance is between 18 ohms and 34000 ohms. Proceed to Test Step 2.Test Step 2. CHECK THE RETURN CIRCUIT OF THE HARNESS
The sensor remains disconnected.
Turn the disconnect switch (if equipped) and the key start switch to the OFF position.
Disconnect the J1 and J2 machine harness connectors from the ECM.
Measure the resistance of the return circuit between contact 2 (wire C216-BK) of the machine harness for the sensor and contact J1-70 of the machine harness for the ECM.Expected Result:The resistance is less than 5 ohms.Results:
OK - The resistance is less than 5 ohms. The harness resistance is correct. Proceed to Test Step 3.
NOT OK - The resistance is greater than 5000 ohms. The ground circuit in the harness has failed. There is an open circuit between the ground contact and frame ground. Repair: Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK FOR A SHORTED HARNESS
The sensor and the ECM remain disconnected from the machine harness.
The disconnect switch and the key start switch remain in the OFF position.
At the machine harness connector for the ECM, measure the resistance between the signal contact J1-22 (wire K977-PK) and all contacts that are used in the machine harness connector for the ECM.Expected Result:Each resistance measurement is greater than 5000 ohms.Results:
OK - Each resistance measurement is greater than 5000 ohms. The ECM may have failed.Repair: Exit this procedure. Perform this diagnostic code procedure again. If the failure is not found, you may need to replace the ECM.Prior to replacing an ECM, always contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time and expense. If the ECM must be replaced, refer to