812945 1 Mercury GEAR

Illustration 1 g00529671
System Schematic For Engine Oil Temperature Sensor (EOTS)The EMCP II+ monitors engine oil temperature in order to protect the engine in case of a problem with the oil temperature. The oil temperature sensor is mounted in an oil gallery of the engine. The exact location of the engine oil temperature sensor varies depending on the engine model.The sensor is powered by an 8 volt sensor supply from the GSC+. The oil 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 fault as an alarm fault. The factory default for P004 is 0. The GSC+ may be programmed to shutdown. P004 is 1 for an oil temperature sensor fault. The operator is not required to press the "Alarm Codes" key in order to view the CID 175 FMI 04. The CID 175 FMI 04 is shown automatically on the upper display.Note: Faults are created when the harness connector is disconnected from the GSC+ during these troubleshooting procedures. Clear these created faults after the particular fault is corrected and the particular fault is cleared. In a properly operating system, the following list of diagnostic fault codes are created when the harness connector is removed from the GSC+.CID 100 FMI 2 - Pressure Sensor (Engine Oil) CID 110 FMI 2 - Temperature Sensor (Engine Coolant)CID 111 FMI 3 - Fluid Level Sensor (Engine Coolant)CID 175 FMI 3 - Temperature Sensor (Engine Oil)CID 190 FMI 3 - Speed Sensor (Engine)CID 336 FMI 2 - Switch (Engine Control)CID 590 FMI 9 - Engine (ECM)A possible cause of a CID 175 FMI 4 is listed below:
A short to battery negative of the sensor signal.Begin performing these procedures only when CID 175 FMI 4 is showing and the "DIAG" indicator is FLASHING on the upper display. The GSC+ treats a CID 175 FMI 4 as an alarm fault. Active alarm faults are shown on the upper 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, use the preceding system schematic. See Testing And Adjusting, "Electrical Connector - Inspect". Clear the fault from the fault log after the troubleshooting is complete.Note: If a Sensor Supply falt (CID 269) is active, correct the fault prior to proceeding with this procedure.
Check The GSC+ And The Harness. Make sure that CID 175 FMI 4 is showing on the display.
Turn the ECS to the OFF/RESET position.
Disconnect the sensor from the engine harness. The sensor remains fastened to the engine.
Turn the ECS to the STOP position.
Press the "Alarm Codes" key.
Check if CID 175 FMI 4 is not showing and CID 175 FMI 3 is now showing.Expected Result: CID 175 FMI 4 is not showing and CID 175 FMI 3 is now showing.Results:
OK: The GSC+ and the harness function properly. The sensor is faulty. Replace the sensor. See Testing And Adjusting, "Pulse Width Modulated (PWM) Sensor - Test" for more testing. STOP.
NOT OK: The CID 175FMI 4 fault remains on the upper display. The harness or the GSC+ is faulty. Proceed to Step 2.
Check The GSC+.
Turn the ECS to the OFF/RESET position.
Disconnect the harness connector from the GSC+.
Turn the ECS to the STOP position.
Press the "Alarm Codes" key.
Check if CID 175 FMI 4 is not showing. Check if CID 175 FMI 3 is now showing.Expected Result: CID 175 FMI 4 is not showing. CID 175 FMI 3 is now showing.Results:
OK: The GSC+ functions properly. Therefore, the signal wire is shorted to battery negative ("B-") in the harness. Troubleshoot the signal wire in the harness between the sensor connector and the GSC+ connector. Also check the electrical connectors and terminals. See Testing And Adjusting, "Electrical Connector - Inspect". STOP.
NOT OK: The CID 175 FMI 4 fault remains on the upper display. The GSC+ is faulty. Replace the GSC+. See Testing And Adjusting, "EMCP Electronic Control (Generator Set) - Replace". STOP.