CLAMP 4N6864 - Caterpillar

Conditions Which Generate This Code:This diagnostic code is associated with the Engine Oil Temperature Sensor. The FMI 3 means that the GSC+ has received an voltage above normal sensor signal.
Illustration 1 g00529671
System Schematic For Engine Oil Temperature Sensor (EOTS)The EMCP II+ system monitors the engine coolant temperature in order to protect the engine from a coolant temperature problem. The coolant temperature sensor is mounted in the water jacket. The exact location of the engine coolant temperature sensor varies depending on the engine model.The sensor is powered by an 8 volt sensor supply from the GSC+. The coolant temperature signal is a pulse width modulated signal. The base frequency of the signal is 455 Hz (370 to 550 Hz). As temperature changes, the duty cycle of the signal varies from 10 to 95 percent.
-40°C (-40°F) is approximately 10% of the duty cycle, which is approximately 1.0 DCV.
135°C (275°F) is approximately 93% of the duty cycle.Note: The GSC+ is usually programmed to treat an oil temperature sensor problem as an alarm fault. The factory default for P004 is 0. The GSC+ may be programmed to shutdown for an oil temperature sensor fault. P004 is 1 for a shutdown. The operator is not required to press the "Alarm Codes" key in order to view the CID 175 FMI 3. The CID 175 FMI 3 is automatically shown on the upper display.The possible causes of a CID 175 FMI 3 are listed below:
A short to the battery positive terminal of the sensor signal.
An open circuit of the sensor signal.Begin performing these procedures only when CID 175 FMI 3 is showing and the "DIAG" indicator is FLASHING on the upper display. The GSC+ treats a CID 175 FMI 3 as an alarm fault. Active alarm faults are shown on the display when the "Alarm Codes" key is pressed. The engine control switch (ECS) must be in any position except the OFF/RESET position. For an inactive fault, the problem may be intermittent. In order to troubleshoot an inactive fault, use the preceding system schematic. See Testing And Adjusting, "Electrical Connector - Inspect". Clear the diagnostic code from the fault log after troubleshooting is complete.Note: If a CID 269 FMI 3 or a CID 269 FMI 4 is active, correct the diagnostic code prior to proceeding with this procedure.Test Step 1. CHECK THE SUPPLY CIRCUIT.
Turn the ECS to the OFF/RESET position and then turn the ECS to the STOP position.
Disconnect the sensor from the engine harness. The sensor remains fastened to the engine.
At the engine harness side of the sensor connector, measure the voltage (DCV) that is between contact "A" and contact "B". Contact "A" is the supply. Contact "B" is the sensor ground.Expected Result:The voltage should be 8.0 0.5 DCV.Results:
OK - The supply circuit functions properly. Proceed to Test Step 2.
NOT OK - The supply circuit has failed. Check the upper display for a CID 269 FMI 3 or a CID 269 FMI 4 and correct the diagnostic code. If these diagnostic codes are