TUBE AS 3376684 - Caterpillar

Illustration 1 g00513776
Schematic for temperature sensor (hydraulic oil)This diagnostic code is recorded when the main display module reads a low sensor signal. As a result of this diagnostic code the corresponding gauge indicates an abnormally high value. The possible causes are listed below:
The sensor has failed.
The signal circuit in the machine harness is shorted to ground.
The main display module has failed.Note: The main display module is unable to determine when a sensor is open or the harness for the sensor signal is open. Also, the main display module is unable to determine when the resistance is too high. This condition is recognized as a gauge that has an indicator at the far left side of the scale.Service Notes: Ensure that the desired diagnostic code is on hold. Ensure that the diagnostic code indicator shows "SERV CODE". The schematic that is shown above represents a typical installation of the component. Verify the connector contact and wire numbers by using the Electrical System Schematic for the machine that is being serviced. 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 The sensor is the cause of the diagnostic code if the diagnostic code is NO longer active.Results: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 main display module may have failed. Proceed to test step 2.
NOT OK - The diagnostic code is NO longer active. The machine harness and the main display module are 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 connector from the main display module.
At the machine harness connector, measure the resistance from contact 17 (443-YL-18) to 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. The short is between the signal circuit (wire 443-YL-18) and the circuit with the low resistance measurement.Repair: 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.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