941303-0800 Tohatsu SPRING WASHER

Illustration 1 g00290291
(1) Data Link
(2) Customer's 24-pin connector
(3) Junction Box
(4) Sensor for fuel rack position
(5) Coolant level sensor
(6) Electronic control module (ECM)
(7) Sensor for transmission oil temperature
(8) Sensor for transmission oil pressure
(9) Atmospheric Pressure Sensor
(10) Engine oil pressure sensor
(11) Speed sensor
(12) Coolant temperature sensor The engines are equipped with various optional engine features and controls. This section provides general information about the engine monitoring and about control devices. This section also reviews the operation of both engines. An engine uses one system to monitor the engine parameters. This system is also used to provide protection for the engine with an engine alarm.In addition to the normal governing and monitoring functions, the Electronic Control Module (ECM) provides basic engine protection for electronically controlled engines. The ECM operates in the following ways:
The ECM diagnoses potential problems.
The ECM initiates corrective action.
The ECM communicates the diagnostics to the engine operator.The severity of a problem determines the corrective action of the ECM. This control module can modify engine performance. The corrective action may totally shut down the engine.When a component trips the alarm, the cause of the alarm must be corrected. Diagnostics are broadcast on an electronic data link. This sends an electronic signal to either of the following components:
The engine's control panel
The electronic displayRefer to your OEM'S manual for a complete description of the display and of the monitoring system. Your OEM will also have information for other protection systems.Coolant Temperature Sensor
This sensor monitors engine coolant temperature. This feature is used for engine system diagnostics with an output from the Electronic Control Module (ECM). The output of the ECM can indicate a high coolant temperature through a relay or through a lamp. In addition, the sensor activates the cold start strategy which improves the engine's startability.High Coolant Temperature Alarm
Coolant level must be maintained in order for the shutoff to function, because the sensing element must be submerged in the coolant to operate.
On 3408 marine engines, the coolant temperature sensor is located at the left rear of the cylinder block. On 3412 marine engines, the coolant temperature sensor is located at the right rear of the cylinder block .When the coolant temperature rises above 104°C (219°F), the coolant temperature switch closes. This activates the coolant temperature alarm.When the coolant temperature drops below 104°C (219°F), the coolant temperature switch opens. This turns off the coolant temperature alarm. You do not need to reset the coolant temperature switch.Failure of Coolant Temperature Sensor
If one of the following conditions exist, a failure of the coolant temperature sensor may have occurred:
Sensor output is open.
Sensor output is shorted to ground.
Sensor output is shorted to supply.
Measured reading of the coolant temperature is out of specification.The ECM will detect the failure of the coolant temperature sensor. The diagnostic lamp will warn the operator about the status of the coolant temperature sensor. The strategies that are related to the coolant temperature will be disabled. A failure of the coolant temperature sensor will not cause a shutdown of the engine or any horsepower change.Coolant Level Sensor
Illustration 2 g00290575The coolant level sensor works in two ways. This sensor monitors the engine's coolant level in order to detect a low coolant level. This sensor also provides information to the Engine Control Module (ECM).Output from the ECM can indicate a low coolant level through a relay or through a lamp. Coolant must be added to the cooling system in order to correct the condition. For more information, see the Operation and Maintenance Manual, "Cooling System Recommendations" (Maintenance Section).Failure of the Coolant Level Sensor
When the output of the coolant level sensor is in one of the following conditions, a failure of the coolant level sensor may have occurred.
Open
Shorted to ground
Shorted to supplyA failure of the coolant level sensor will not cause a shutdown of the engine or a change in horsepower.The Engine Control Module (ECM) will detect a failure of the coolant level sensor. The Engine Control Module then warns the operator through a warning lamp.Engine Oil Pressure Sensor
Illustration 3 g00290690
Engine Oil Pressure Sensor
Illustration 4 g00290693
Engine Oil Pressure Graph
(X) Engine RPM in kPa
(Y) Engine oil pressure
(1) Sufficient pressure
(2) Insufficient pressure Low Oil Pressure
The engine oil pressure sensor detects engine oil pressure for diagnostic purposes. The engine oil pressure sensor sends a signal to the Electronic Control Module (ECM). No resetting procedure is required.Low Oil Pressure Warning
The ECM monitors engine oil pressure (Y) and engine rpm (X) in order to detect an unacceptable low oil pressure condition. If the customer has specified this parameter and if this condition exists, an event is logged and a warning signal is transmitted.Note: Mechanically controlled engines can be equipped with an oil temperature gauge and with an oil pressure gauge.Very Low Oil Pressure Warning
The ECM monitors engine oil pressure (Y) and engine RPM (X) in order to detect a very low oil pressure condition that is dangerous. If the customer has specified this parameter and if this condition exists, a fault is logged and a warning signal is transmitted. If the customer has specified the "DERATE" parameter, the ECM will slow the engine to a safe operating range.Failure of the Engine's Oil Pressure Sensor
If one of the following conditions exist, a failure of the engine's oil pressure sensor may have occurred:
Engine oil pressure sensor's output is open.
Engine oil pressure sensor's output is shorted to ground.
Engine oil pressure sensor's output is shorted to electrical power supply.
Measured reading of the oil pressure is out of specification.The ECM will detect a failure of the engine oil pressure sensor. The diagnostic lamp warns the operator about the status of the engine oil pressure sensor. The related strategies for oil pressure will be disabled. A failure of the engine o