TIP-PENETRATION 9W8459 - Caterpillar

Sensor Locations
Illustration 1, Illustration 2, Illustration 3, and Illustration 4 show the typical locations of the sensors for a 3176B Marine Engine. Specific engines may appear different from the illustrations due to differences in applications.
Illustration 1 g00579598
Front view of engine (1) Coolant temperature sensor (2) Speed/timing sensor (3) Backup speed/timing sensor
Illustration 2 g00579639
Right side view of engine (4) Oil pressure sensor
Illustration 3 g00579766
Left side view of engine (5) Coolant level sensor (6) Fuel temperature sensor (7) Fuel pressure sensor
Illustration 4 g00579601
Top view of engine (8) Inlet manifold air temperature sensor (9) Inlet manifold air pressure sensorFailure of Sensors
All Sensors
A failure of any of the sensors may be caused by one of the following malfunctions:
Sensor output is open.
Sensor output is shorted to "- battery" or "+ battery".
Measured reading of the sensor is out of specification.Atmospheric Pressure Sensor
Atmospheric pressure sensor (6) measures the atmospheric pressure in the crankcase. A signal is sent to the Electronic Control Module (ECM).
Table 1
Atmospheric Pressure Sensor    
Operating pressure range for the atmospheric pressure sensor    
0 to 116 kPa (0 to 16.8 psi)    Coolant Temperature Sensor
Coolant temperature sensor (1) monitors engine coolant temperature. This feature is used for engine system diagnostics with an output from the ECM. The output of the ECM can indicate a high coolant temperature through a relay or a lamp. In addition, the sensor activates the cold start strategy which improves the startability of the engine.Failure of the 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 or supply.
Measured reading of the coolant temperature is out of specification.The ECM will detect a failure of the coolant temperature sensor. The diagnostic lamp will warn the operator about the status of the coolant temperature sensor. Coolant temperature related strategies will be disabled if a failure occurs. A failure of the coolant temperature sensor will not cause a shutdown of the engine or any horsepower change.Coolant Level Sensor
Note: Coolant level sensor (5) is an optional feature.Coolant level sensor (5) monitors the level of the engine coolant. The coolant level sensor is used to detect a condition when the coolant level is low. The coolant level sensor provides information to the ECM. The output from the ECM can indicate low coolant level through a relay or a lamp. Coolant must be added to the cooling system in order to correct the condition.The system can be programmed with one of the following options:ENABLED - The system will monitor the input from the coolant level sensor. The system is programmed with this value when the engine is shipped by Caterpillar.DISABLED - The system will not monitor the input from the coolant level sensor. All of the diagnostics that are associated with the coolant level sensor will be disabled.Failure of the Coolant Level Sensor
A failure of the coolant level sensor may occur under the following conditions:
The coolant level sensor is open.
The coolant level sensor is shorted to ground.
The coolant level sensor is