SWITCH 3C8497 - Caterpillar

Illustration 1 g01193071
Schematic of the Temperature Sensor for the Torque Converter Oil
The torque converter oil temperature sensor is located on the torque converter housing.This diagnostic code is recorded when the ECM reads the voltage from the temperature sensor as being below normal or shorted to ground.The possible causes of this diagnostic code are listed:
A shorted harness
A failed sensor
The ECM has failed. This is unlikely.Note: Ensure that the diagnostic code is active.Note: The following procedure can create numerous related diagnostic codes. Complete the following procedure. Reconnect all harnesses. Then, the related diagnostic codes will be shown as being NOT active. Then, clear all of the related diagnostic codes.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 active.
Observe the status of the diagnostic code. Disconnect the machine harness from the sensor. Expected Result:The diagnostic code will remain active if the sensor is not the cause of the diagnostic code. The sensor is the cause of the diagnostic code if the diagnostic code is NO longer active.Results:
OK - The diagnostic code remains active. The sensor has NOT failed. The machine harness may have failed or the ECM may have failed. Proceed to test step 2.
NOT OK - The diagnostic code is NO longer active. The machine harness and the ECM are operating properly.Repair: The sensor has failed. Replace the sensor.STOPTest Step 2. CHECK THE SIGNAL CIRCUIT FOR A SHORT TO GROUND.
The sensor remains disconnected from the machine harness.
Turn the key start switch and the disconnect switch to the OFF position.
Disconnect the machine harness connector J1 and J2 from the ECM.
At the machine harness connector J2, measure the resistance from contact J2-24 (F704-OR(Orange)) to all possible sources of ground. The possible sources of ground are contacts: J1-3, J1-5, J1-7, J1-13, J1-20, J1-20, J1-23, J1-57, J1-60, J1-70, J2-22, J2-63 and frame ground. Expected Result:The resistance should be greater than 5000 ohms. Results:
OK - The resistance is greater than 5000 ohms. The machine harness is correct. Proceed to test step 3.
NOT OK - The resistance is less than 5000 ohms. There is a short in the machine harness.Repair: The short is between the signal circuit (wire F704-OR(Orange)) and the circuit with the low resistance measurement. Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS.
Clean the contacts of the harness connectors.
Reconnect all harness connectors.
Observe the status of the diagnostic code.
Operate the machine.
Observe the status of the diagnostic code. Expected Result:The diagnostic code is NO longer active.Results:
YES - The diagnostic code is NO longer active. The diagnostic code does not exist at this time. The initial diagnostic code was probably caused by a poor electrical connection and/or a short at one of the harness connectors that was disconnected and then reconnected. Resume normal machine operation.STOP
NO - The diagnostic code has not been corrected. The ECM has failed.Repair: It is unlikely that the ECM has failed. Exit this procedure and perform this diagnostic code procedure again.