a) Air Flow Sensor : 

Air flow sensor is a device that is used in conjunction with an oxygen sensor to accurately measure the flow of air into a fuel injection engine. Normally, it is located on throttle body. 

b) Air Temperature Sensor : 

The air temperature sensor is used to measure the temperature of the incoming air in the engines air stream. The sensor is used by the computer to measure air density for fuel mixture control. The computer uses this information to change the air/fuel ratio according to the air density. Normally, it is located on intake manifold. 

c) Oxygen Sensor : 

The Oxygen sensor is a device positioned in the exhaust manifold/ stream. Oxygen sensor, measures the make-up of the exhaust whether it is running too lean or too rich. 

d) Throttle Position Sensor : 

The purpose of the throttle position sensor/switch is to relay the position of the throttle butterfly valve to the ECU. Normally, it is located on throttle body. 

e) Vehicle Speed Sensor : 

Normally, the vehicle speed sensor is located on transmission box/ gear box housing. The vehicle speed sensor (VSS) measures transmission/transaxle output or wheel speed. The ECM uses this information to modify engine functions such as ignition timing, air/fuel ratio, transmission shift points, and to initiate diagnostic routines.