BRACKET AS 4518513 - Caterpillar

Diagnostic Codes
When the ECM detects an electronic system problem, the ECM generates a diagnostic code. Logged diagnostic codes will be cleared from the "Logged Diagnostic Codes" screen when the code has not been active for 40 hours. Diagnostic codes are provided in order to indicate that the ECM has detected an electrical problem or an electronic problem with the engine control system. In some cases, the engine performance can be affected when the condition that is causing the code exists.If the operator indicates that a performance problem occurs, the diagnostic code may indicate the cause of the problem. Use a laptop computer to access the diagnostic codes. The problem should then be corrected.Event Codes
Event Codes are used to indicate that the ECM has detected an abnormal engine operating condition. The ECM will log the occurrence of the event code. This does not indicate an electrical malfunction or an electronic malfunction. If the temperature of the coolant in the engine is higher than the permitted limit, then the ECM will detect the condition. The ECM will then log an event code for the condition.Speed/Timing Sensors
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Typical exampleThe crankshaft speed/timing sensor generates a signal by detecting the movement of the teeth that are located on the crankshaft timing ring (1) . The signal that is generated by the speed/timing sensor is transmitted to the ECM. The ECM uses the signal from the speed/timing sensor to calculate the position of the crankshaft. The signal is also used to determine the engine speed.
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Typical exampleThe camshaft speed/timing sensor generates a signal that is related to the camshaft position. The camshaft speed/timing sensor detects the movement of the position wheel on the front of the camshaft (2) . The signal that is generated by the speed/timing sensor is transmitted to the ECM. The ECM calculates the speed and the rotational position of the engine by using the signal.
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Schematic for speed/timing sensorWhen the engine is cranking, the ECM uses the signal from the speed/timing sensor on the camshaft. When the engine is running the ECM uses the signal from the speed/timing sensor on the crankshaft. This speed/timing sensor is the primary source of the engine position.Pressure Sensors
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Schematic for the pressure sensors for the greater than 56 kW (75 hp) C3.4B engine
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Schematic for the pressure sensors for the less than 56 kW (75 hp) C3.4B engine
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Schematic for the DPF differential pressure sensor on certain C3.4B enginesNote: The DPF differential pressure sensor is only applicable to engines equipped with a wall flow DPF.The boost pressure sensor is an active sensor.The boost pressure sensor provides the ECM with a measurement of inlet manifold pressure in order to control the air/fuel ratio. This will reduce the engine smoke during transient conditions.An engine oil pressure switch is installed to the engine. While the engine is running and oil pressure is detected, the switch will be open. When no oil pressure is detected, the switch will be closed.The ECM can warn the operator of possible conditions