Circuit Description

The TP sensor is mounted on the throttle body and detects the throttle valve opening angle.

When the throttle valve is fully closed, the sensor transmits a signal voltage of approximately 0.3 to 1.0 V to terminal VTA of the ECM. This signal voltage increases in proportion to the opening angle of the throttle valve, reaching approximately 3.2 to 4.9 when the throttle valve is fully open.

The ECM determines the vehicle driving conditions from these signals and uses this information in functions such as air-fuel ratio correction, power increase correction and fuel-cut control.

Fig 1: Throttle Position Sensor Circuit

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 2: DTC P0120, P0122, P0123 Detection Condition Trouble Area Chart

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

• Fail-safe mode: When any of these DTCs are set, the ECM enters fail-safe mode. During fail-safe mode, the ECM cuts fuel intermittently. Fail-safe mode continues until a pass condition detected and the ignition switch is turned to OFF.
• When any of these DTCs are set, check the throttle valve opening angle using a hand-held tester or OBD II scan tool.