5010240JP Mercruiser STERN DRIVE UNIT

The Electronic Control Module (ECM) supplies 5.0 0.2 VDC from the ECM connector J1/P1 to each analog sensor connector. The sensor return line connects to the ECM connector J1/P1. The analog sensor supply is output short circuit protected. A short circuit to the battery will not damage the circuit inside the ECM.Note: The analog sensors are not protected from overvoltage. A short from the supply line to the +Battery may damage the sensors. If the CID-FMI 262-03 is logged, it is possible that all of the analog sensors have been damaged. Repair the analog sensor supply and check for any "ACTIVE" sensor diagnostic codes in order to determine if a sensor has failed.Note: Parameters may affect the behavior of the engine. Users can use Caterpillar Electronic Technician (ET) in order to monitor parameter settings: warnings, derates, shutdown override setpoints and delay times. The behavior of the ECM may vary from the description that is given in this system operation section. Refer to the diagnostic procedure Troubleshooting, "System Configuration Parameters" in order to determine if there are any parameters that are affecting engine operation.The following list contains a description of the analog sensors that are found on the engine.Aftercooler Temperature Sensor - The ECM uses the signal from the sensor to monitor changes in system temperature. This sensor is used in conjunction with the brake oil temperature sensor and the coolant temperature sensor in order to control the fan clutch. The ECM makes adjustments to the system as the engine temperature changes. This allows the engine to operate at optimal performance through a wide range of operating temperatures. The sensor output is a DC voltage that varies with aftercooler temperature. The output signal is a DC voltage between 0.2 VDC and 4.8 VDC. The operating range of the sensor is -40 °C to 120 °C (-40 °F to 248 °F).Coolant Temperature Sensor - The engine coolant temperature sensor measures the temperature of the engine coolant. The sensor output is a DC voltage that varies with engine coolant temperature between 0.2 VDC and 4.8 VDC. The operating range of the sensor is -40 °C to 120 °C (-40 °F to 248 °F). The engine uses a strategy of cold mode in order to improve the engine starting ability. Cold mode operation helps to control white smoke during cold starts. Cold mode operation helps to improve warm up time of the engine. The ECM uses the information from the coolant temperature sensor to set the mode of operation. The engine will operate in cold mode and in normal mode during operation. In normal mode, injection timing is varied as a function of engine speed and of engine load. The process of combustion is improved by controlling the injection timing in cold mode. Once the engine has started, the strategy for cold mode idle (700 rpm) is active for ten minutes following initial start-up. The ten minute delay allows the operator to perform a walk around inspection of the engine. Engine idle is then elevated when engine coolant temperature is below 70 °C (158 °F). Engine speed will increase up to 1300 rpm if the engine coolant temperature falls below 60 °C (140 °F). Engine speed will increase from low idle (700 rpm) to the elevated idle speed at a rate of 33 rpm per second when the engine's elevated low idle strategy is activated. The elevated idle can be disabled by depressing the machine's throttle pedal past twenty five percent of full throttle. This will allow the low engine idle to remain operational for another ten minutes if the previous conditions exist. Cold mode idle will remain active until the coolant temperature rises above 63 °C (145 °F).Engine Oil Pressure Sensor - The ECM uses this sensor to detect low engine oil pressure which may indicate a failed engine oil pump, oil leakage, or low pressure in the engine oil filter. The signal is compared with a map of engine oil pressure versus engine rpm which is stored in the ECM. The sensor output is a DC voltage that varies with engine oil pressure between 0.2 VDC and 4.8 VDC. The operating range of the sensor is 0.0 kPa to 1090 kPa (0.0 psi to 158 psi). The ECM calibrates the sensor within the first five seconds after power is applied to the ECM. The ECM checks the sensor value against an acceptable pressure range. If the pressure value is not in this range, the previous calibration will be used. Perform a manual calibration of the sensor if the sensor or the ECM