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Home >> Toyota >> 2005 >> Camry Base, Standard >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System (SFI) (2AZ-FE) - Diagnostics >> DTC P0121: Throttle/Pedal Position Sensor/Switch "A" Circuit Range/Performance Problem >> Monitor Description
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Monitor Description

The ECM uses the throttle position sensor to monitor the throttle valve opening angle.

This sensor includes 2 signals: VTA1*1 /VTA*2 and VTA2. VTA1*1 /VTA*2 is used to detect the throttle opening angle and VTA2 is used to detect malfunctions in VTA1*1 /VTA*2 . There are several checks that the ECM performs confirm proper operation of the throttle position sensor and VTA1*1 /VTA*2 .

There is a specific voltage difference expected between VTA1*1 /VTA *2 and VTA2 for each throttle opening angle.

If the voltage output difference of the VTA1*1 /VTA*2 and VTA2 deviates from the normal operating range, the ECM interprets this as a malfunction of the throttle position sensor. The ECM will turn on the MIL and a DTC is set.

*1 : Except PZEV

*2 : PZEV