SEAL AS 9X7397 - Caterpillar

Sensor Locations
Illustration 1 shows the typical locations of the sensors for a 3126B Industrial Engine. Specific engines may appear different from the illustration due to differences in applications.
Illustration 1 g00805525
Typical example
Left side view
(1) Injection actuation pressure sensor
(2) Inlet air temperature sensor
(3) Atmospheric pressure sensor
(4) Boost pressure sensor
(5) Engine oil temperature sensor
(6) Engine speed/timing sensor
(7) Coolant temperature sensor
(8) Engine oil pressure sensor Failure 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 (3) 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 0 to 116 kPa (0 to 16.8 psi) Boost Pressure Sensor
Boost pressure sensor (4) provides a signal which corresponds to turbocharger outlet pressure to the ECM. The air/fuel ratio control utilizes the actual engine speed and the turbocharger outlet pressure in order to control the transient smoke level. The ECM can control injection timing and the amount of fuel that is injected. When the throttle is increased and when the engine demands more fuel, the fuel limit is controlled in order to reduce overall smoke levels of the engine exhaust.Failure of the Boost Pressure Sensor
The ECM will detect failure of the boost pressure sensor. The operator will be warned of the problem through the diagnostic lamp. The strategies that are related to the boost will be disabled. Engine power will be severely reduced in the event of a failure of the boost pressure sensor. A failure of the boost pressure sensor will not cause a shutdown of the engine.Coolant Temperature Sensor
Coolant temperature sensor (7) monitors engine coolant temperature. The output of the ECM can indicate a high coolant temperature through a relay or a lamp. The coolant temperature sensor is used by the ECM to determine initiation of the Cold Start Strategy.
Table 2
Coolant Temperature Sensor
Activation temperature for the high coolant temperature fault 103°C (217°F)
Activation temperature for the very high coolant temperature fault 106°C (229°F) Failure of the Coolant Temperature Sensor
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. A failure of the coolant temperature sensor will not cause a shutdown of the engine or any horsepower change.Engine Oil Pressure Sensor
Engine oil pressure sensor (8) is an absolute pressure sensor that measures the engine oil pressure in the main oil gallery. The engine oil pressure sensor detects engine oil pressure for diagnostic purposes. The engine oil pressure sensor sends a signal to the ECM.
Table 3
Engine Oil Pressure Sensor
Operating pressure range 0 to 690 kPa (0 to 100 psi) Low Oil Pressure Warning
The setpoint is dependent upon the engine speed. The fault will be active and logged only if the engine has been running for more than 15 seconds. Very Low Oil Pressure