LINES GP-AIR 8N0848 - Caterpillar

Sensors
Sensors provide information to the ECM. The information enables the ECM to control the engine as efficiently as possible over a wide range of operating conditions. The information is used for monitoring engine operation and for engine protection.Illustrations 2, 3, and 4 show the locations of the sensors.
Illustration 2 g00919486
(1) Coolant pressure switch (pump inlet pressure) (2) Detonation sensor (3) Electrohydraulic actuator pressure switch (EPG) (4) Inlet air temperature sensor (5) Engine coolant temperature sensor
Illustration 3 g01090467
(6) Pressure sensor for unfiltered oil (7) Pressure sensor for filtered oil (8) Engine coolant pressure sensor (outlet) (9) Oxygen sensor (10) Atmospheric pressure sensor (11) Manifold air pressure sensor (12) Engine oil temperature sensor (13) Oxygen buffer (14) Speed/timing sensor (15) Boost pressure sensor (16) Humidity sensorThe functions of the sensors are described below.Coolant pressure switch (1) - A pressure switch that monitors the pump inlet pressure is located at the outlet of the oil cooler.Detonation sensors (2) - The detonation sensors monitor the engine for detonation in each cylinder. To eliminate detonation, the ECM retards the timing of the cylinder. If excessive detonation continues, the ECM will shut down the engine.Electrohydraulic actuator pressure switch (3) - The electrohydraulic actuator pressure switch monitors the pressure of the oil supply. Insufficient oil pressure will activate an engine shutdown.Inlet air temperature sensor (4) - A sensor for monitoring the air inlet temperature is located in the elbow before the number one cylinder head. Excessive inlet air temperature can activate an alarm, a derating, or a shutdown.Engine coolant temperature sensor (5) - The temperature sensor is located in the water temperature regulator housing. To monitor the coolant temperature, the element must be in contact with the coolant. If overheating occurs due to low coolant level, the sensor will not function properly. A high coolant temperature will activate an alarm, a derating, or a shutdown. A low coolant temperature will only activate an alarm. The setpoints for the activation can be programmed with the ET. The engine can be restarted after a shutdown due to high engine coolant temperature. However, another shutdown will occur after one minute if the temperature remains high.Oil pressure sensors (6) and (7) - The engine oil pressure is measured before the oil filters and after the oil filters. An alarm or a shutdown can be activated by any of the following occurrences: low filtered oil pressure, low oil filter differential pressure and high oil filter differential pressure.Engine coolant pressure sensor (8) - A pressure switch is located at the outlet for the engine jacket water. If the outlet pressure is too low, the ECM will activate a shutdown.Oxygen sensor (9) and oxygen buffer (13) - The oxygen sensor and the oxygen buffer generate a signal that is proportional to the percent of oxygen in the exhaust. The signal is used for adjusting the air/fuel ratio in order to achieve the level of emissions that is desired.Atmospheric pressure sensor (10) - The sensor monitors the atmospheric pressure. The master ECM uses the signal