OIL 7X2603 - Caterpillar

Illustration 1 g00443488
Schematic for temperature sensor (engine coolant)
This diagnostic code is recorded when the main display module reads the sensor signal as being too low. As a result of this diagnostic code the corresponding gauge will indicate 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 when the harness has an open. 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 MAIN DISPLAY MODULE AND THE HARNESS.
Turn the disconnect switch and the key start switch to the ON position.
The diagnostic code indicator should show "SERV CODE".
Disconnect the machine harness from the sensor that is causing the problem.
Observe the diagnostic code indicator. Expected Result:The diagnostic code indicator is ON.Results:
YES - The diagnostic code indicator stays ON. The harness wiring or the main display module has failed. Proceed to test step 2.
NO - The diagnostic code indicator turns OFF. The sensor has failed.Repair: Replace the sensor.STOPTest Step 2. CHECK THE SIGNAL WIRE FOR A SHORT TO GROUND.
The machine harness remains disconnected from the sensor.
The disconnect switch and the key start switch remain in the ON position.
At the machine harness connector for the sensor, measure the voltage. Measure the voltage from contact "C" (wire 441-OR(Orange)) and frame ground. Expected Result:The voltage that is measured is within one of the following specifications.Results:
6.0 0.5 DCV - The voltage is 6.0 0.5 DCV. The voltage is correct. Verify that the diagnostic code is still present. Repair: It is unlikely that the main display module has failed. Exit this procedure and perform this procedure again. Also, recheck if the diagnostic code indicator is illuminated for this diagnostic code. If the cause of the diagnostic code is not found, replace the main display module. See Testing and Adjusting, "Module - Replace".STOP
LESS THAN 0.5 DCV - The voltage is less than 0.5 DCV. The harness wiring has failed. There is