Failsafe of Throttle Position Sensor

The throttle position sensor comprises two (Main, Sub) sensor circuits.

If a malfunction occurs in either of the sensor circuits, the ECM detects the abnormal signal voltage difference between these two sensor circuits, cuts off the current to the throttle control motor, and switches to the limp mode.

Then, the force of the return spring causes the throttle valve to return and stay at the prescribed opening. At this time, the vehicle can be driven in limp mode while the engine output is regulated through the control of the fuel injection and ignition timing in accordance with the accelerator opening.

The same control as above is effected if the ECM detects a malfunction in the throttle control motor system.


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