HOSE 1490688 - Caterpillar

Sensor Locations
Illustration 1 shows the typical locations of the sensors for this engine. Specific engines may appear different from the illustration due to differences in applications.
Illustration 1 g00851903
Left side view (1) Injection actuation pressure control valve (IAPCV) (2) Rail pressure sensor (3) Coolant temperature sensor (4) Oil temperature sensor (5) Inlet air temperature sensor (6) Boost pressure sensor (7) Engine control module (ECM) (8) Oil pressure sensor (9) Speed/Timing sensorsFailure 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.Boost Pressure Sensor
Boost pressure sensor (6) 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 (3) 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 1
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. The cold start strategies will be disabled if failure occurs. A failure of the coolant temperature sensor will not cause a shutdown of the engine or any horsepower change.Engine Oil Temperature Sensor
Engine oil temperature sensor (4) monitors the temperature of the engine oil. The ECM uses the information from the engine oil temperature sensor in order to adjust the timing of the fuel injection and the pressure of the fuel injection.
Table 2
Engine Oil Temperature Sensor    
Operating temperature range    
-40 to 120°C (-40 to 258°F)    Engine Speed/Timing Sensor
If the ECM does not receive a signal from primary speed/timing sensor (9), the "DIAGNOSTIC" lamp will indicate a diagnostic fault code which will be logged in the ECM memory. If the ECM does not receive a