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| Illustration 1 | g01237417 |
Engine monitoring circuit | |
The components of the engine monitoring circuit are the Engine Electronic Control Module (Engine ECM), the Power Train Electronic Control Module (Power Train ECM), the Caterpillar Monitoring System ECM, the coolant level sensor, the engine coolant temperature sensor, the intake manifold pressure sensor, the intake air temperature sensor, the engine oil pressure sensor, and the fuel rail pressure sensor.
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| Illustration 2 | g01226156 |
(1) Coolant level sensor | |
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| Illustration 3 | g01236919 |
(2) Power Train ECM | |
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| Illustration 4 | g01226150 |
(3) Caterpillar Monitoring System ECM (behind display) (4) Coolant level alert indicator | |
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| Illustration 5 | g01240566 |
(5) Engine ECM | |
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| Illustration 6 | g01226153 |
(6) Coolant temperature gauge | |
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| Illustration 7 | g01247415 |
(7) Coolant temperature sensor (8) Intake manifold pressure sensor (9) Intake air temperature sensor (10) Fuel rail pressure sensor (11) Engine oil pressure sensor | |
With the key start switch in the ON position, 24 volt power is supplied from the batteries via circuit breaker 6 to Engine ECM (5), via circuit breaker 13 to Caterpillar Monitoring System ECM (3) and via circuit breaker 14 to Power Train ECM (2). Engine ECM (5) supplies 5 volt power to intake air temperature sensor (9), intake manifold pressure sensor (8), engine oil pressure sensor (11), engine coolant temperature sensor (7), and fuel rail pressure sensor (10). Power Train ECM (2) supplies 8 volt power to engine coolant level sensor (1) .
Engine coolant level sensor (1) sends a signal to Power Train ECM (2) which indicates whether coolant fluid is at the correct level in the radiator header tank, if not Power Train ECM (2) will record the fault. This fault is then sent to Caterpillar Monitoring System ECM (3) via the CAT Data Link. Caterpillar Monitoring System ECM (3) registers the fault and turns on engine coolant level alert indicator (4) .
A signal is sent from engine coolant temperature sensor (7) to Engine ECM (5). Engine ECM (5) sends a signal via the CAT Data Link to Caterpillar Monitoring System ECM (3). Caterpillar Monitoring System ECM (3) sends a signal to coolant temperature gauge (6). Coolant temperature gauge (6) displays the engine coolant temperature.
Engine coolant temperature sensor (7), intake manifold pressure sensor (8), intake air temperature sensor (9), fuel rail pressure sensor (10), and engine oil pressure sensor (11) sends signals to Engine ECM (5). Engine ECM (5) compares these signals with the changing engine requirements and monitors them within a normal range.
If the signal from engine coolant temperature sensor (7), intake manifold pressure sensor (8), intake air temperature sensor (9), fuel rail pressure sensor (10) or engine oil pressure sensor (11) is out of range for the engines requirements, Engine ECM (5) will begin timing the conditions. Engine ECM (5) monitors the condition of the sensors and will derate the engine or shut the engine down depending on the severity of the conditions.
ReferenceFor more information on the engine monitoring system, refer to Operation and Maintenance Manual, "Caterpillar Monitoring System".