Saturday, September 4, 2010

Throttle Position Switch




The throttle position switch is also know as Idle Control Switch. This switch closes when the throttle valve is closed, it point ECM measure 0V as well as 0V in the Idle terminal. When the throttle opens the switch opens as well and the ECM reads positive voltage at the Idle circuit. The TPS switch is located at the throttle housing. The TPS switch looks different from the TPS sensor and the throttle switch is square.


Difference between TPS sensor and TPS switch

A TPS sensor is variable resistor which tells the engine computer the absolute throttle opening percentage.
The switch tells the system when the throttle is wide open for enrichment purpose.


Explain the internal operation of this sensor and why resistance changes.

When the throttle closes the Ohmeter should read Zeror Ohms, however the throttle opens the Ohmeter should read infinite. The switch in resistance must occur as soon as the throttle start to open.

Meter readings of my experiments were as following:
Wire : B/G = Over 20 Mega Ohms (Close Position) and 0.00 Ohms (Open Position)
Wire : B/Y = 0.00 Ohms (Close Position) and Over 20 Mega Ohms (Open Position)

Wiring Diagram


No comments:

Post a Comment