COVER 3C8537 - Caterpillar

Illustration 1 g01195375
Schematic of the Transmission Oil Temperature Sensor
This diagnostic code is recorded when the ECM reads the voltage of the temperature sensor as being below normal. The voltage of the signal wire is below normal and/or shorted to ground. The possible causes of this diagnostic code are listed here:
The sensor has failed.
The signal circuit in the machine harness is shorted to ground.
The ECM has failed. This is unlikely.Test Step 1. CHECK THE SENSOR.
Turn the disconnect switch and the key start switch to the ON position.
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 active. If the sensor has failed, the diagnostic code is NO longer active.Results:
OK - The diagnostic code is active. The sensor is not causing the diagnostic code. The machine harness or the ECM may have failed. Proceed to test step 2.
NOT OK - This diagnostic code is NO longer active. The machine harness is correct and the ECM is operating properly. The sensor has failed.Repair: 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 from the ECM.
At the machine harness connector for the ECM, measure the resistance between the signal contact and frame ground. Expected Result:The resistance is greater than 5.0 ohms.Results:
OK - The resistance is greater than 5.0 ohms. The harness circuit resistance is correct. Proceed to test step 3.
NOT OK - Resistance is less than 5.0 ohms. The machine harness has failed.Repair: There is a short between frame ground and the signal circuit in the machine harness. 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.
Turn the disconnect switch and the key start switch to the ON position.
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 Expected Result:The diagnostic code is no longer active.Results: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 NOT active. The diagnostic code does not exist at this time. The initial diagnostic code was probably caused by a poor electrical connection 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 procedure again. If the cause of the diagnostic code is not found, then replace the ECM. See Testing and Adjusting, " Electronic Control Module (ECM) - Replace".STOP