EMS Sensors

EMS Sensors

The EMS incorporates the following sensors: l An APP sensor. l A Crankshaft Position (CKP) sensor. l A Camshaft Position (CMP) sensor. l A Mass Air Flow (MAF) sensor. l An Intake Air Temperature (IAT) sensor. l An Engine Coolant Temperature (ECT) sensor. l A thermostat monitoring sensor. l Four Heated Oxygen Sensors (HO2S). l Two knock sensors.

APP Sensor

The APP sensor enables the ECM to determine the throttle position requested by the driver on the accelerator pedal.

The APP sensor is installed on the pedal box and consists of a twin track potentiometer with wipers driven by a linkage connected to the accelerator pedal. Each potentiometer track has a 5 volt supply and ground connection from the ECM, and produces a linear signal voltage to the ECM proportional to the position of the accelerator pedal. The signal voltage from track 1 of the potentiometer is approximately double that of the signal voltage from track 2.

From the sensor signals, the ECM determines driver demand as a percentage of pedal travel, where 0% is with the pedal released and 100% is with the pedal fully depressed. Driver demand is then used to calculate throttle angle, fuel quantity and ignition timing. The ECM also outputs driver demand on the CAN system, for use by the brake and gearbox control systems.

The ECM stores the signal values that correspond with closed and wide open throttle, and adapts to new values to accommodate component wear or replacement.