Description

DATA TROUBLE CODE: P0121

SYSTEM:

CIRCUIT DESCRIPTION
The Throttle Position Sensor is mounted in the Throttle Body and detects the throttle valve opening angle. When the throttle valve is fully closed, the IDL contacts in the Throttle Position Sensor are on, so the voltage at the terminal IDL of the Engine Control Module becomes 0 volts. At this time, a voltage of approximately 0.7 volts is applied to terminal VTA of the Engine Control Module. When the throttle valve is opened, the IDL contacts go off and thus the power source voltage of approximately 12 volts in the Engine Control Module is applied to the terminal IDL of the Engine Control Module. The voltage applied to the terminal VTA of the Engine Control Module increases in proportion to the opening angle of the throttle valve and becomes approximately 3.5 - 5.0 volts when the throttle valve is fully opened. The Engine Control Module judges the vehicle driving conditions from these signals input from terminals VTA and IDL, and uses them as one of the conditions for deciding the air-fuel ratio correction, power increases correction and fuel-cut control etc.


DIAGNOSTIC TROUBLE CODE DETECTING CONDITION
- When closed throttle position switch is ON, the following condition continues: VTA voltage is greater than 2.0 volts. (2 trip detection logic).

TROUBLE AREA
- Throttle Position Sensor.