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provide optimum driver control under all conditions. minimize evaporative emissions. provide system diagnostics. In addition to these functions the ECM also interfaces with other vehicle systems through the controller area network (CAN). Camshaft Position (CMP) Sensor The camshaft position (CMP) sensors monitor the position of both camshafts to allow the ECM to control the phase of the inlet camshafts relative to the position of the crankshaft. Variable Camshaft Timing Oil Control Solenoid The variable camshaft timing oil control solenoid is a hydraulic actuator, which advances and retards the inlet camshaft timing, thereby altering the camshaft to crankshaft phasing for optimum engine performance. Intake Manifold Tuning (IMT) Valve There are two intake manifold tuning (IMT) valves, an upper and a lower, sometimes referred to as number one and two respectively. They are a two position (open and close) device used to create a variable air intake system. The IMT valve positions are switched by signals from the ECM to optimize torque across the engine's speed and load range. The upper IMT valve opens between 4,100 and 6,150 rpm while the lower IMT valve opens between 3,900 and 6,150 rpm. Knock Sensors (KS) The knock sensors (KS) detect combustion knock within the engine cylinders and sends a signal to the ECM. The ECM uses this information to gradually adjust the ignition timing until the combustion knock is eliminated. Mass Air flow (MAF) Sensor The mass air flow (MAF) sensor informs the ECM of the rate of air flow entering the engine by producing a voltage which is proportional to the rate of air flow into the engine. The voltage produced by the MAF sensor increases as the rate of air flow increases. The ECM also takes into account the density of the air entering the air intake system so that it is possible to maintain the required air to fuel ratio, and to compensate for variations in atmospheric pressure.
Integral to the MAF sensor is the intake air temperature sensor (IAT) which measures the temperature of the air entering the air intake system. The ECM uses this information to compensate for higher than normal air intake temperatures. Fuel Rail Pressure (FRP) Sensor The fuel rail pressure (FRP) sensor is a pressure transducer device. A vacuum pipe connects to the intake manifold for manifold pressure. The ECM receives a voltage from the FRP sensor which is proportional to the fuel pressure in the fuel injection supply manifold. |