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Home >> Buick >> 2004 >> Rainier 4.2 S, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - 4.2L (Introduction) >> Description and Operation >> Throttle Actuator Control (TAC) System Description >> Throttle Body Assembly
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Throttle Body Assembly

The throttle body for the TAC system is similar to a conventional throttle body with several exceptions. One exception being the use of a motor to control the throttle position instead of a mechanical cable. Another exception is the throttle position (TP) sensor. The TP sensor is mounted in the throttle body assembly. The TP sensor is 2 individual TP sensors within the throttle body assembly. Two separate signal, low reference, and 5-volt reference circuits are used to connect the TP sensors and the PCM. TP sensor 2 signal voltage increases as the throttle opens. TP sensor 1 signal voltage decreases as the throttle opens.