Throttle Position Sensor: Description
The sensor is a variable resistor, which is used to determine the position of the throttle plate and the rate of change in its angle. A software strategy within the ECM enables the closed throttle position to be learned, enabling the sensor to be fitted without the need for adjustment. The signal is used by the ECM as part of the transient fuelling strategy and to determine the closed throttle position for idle speed control, in conjunction with road speed.
The signal is not only checked for range (exceeds a minimum or maximum threshold), but also for plausibility against MAF. If the load-monitoring fault is stored, it is indicative of a blocked air filter or collapsed air intake duct etc. It is also probable that the altitude adaptation factor is incorrect under these conditions. For throttle position sensor testing, see Fig 1 .