General Information

Engine Control
P0638 Throttle Actuator Control Range / Performance - General Information

Component Location





General Description

The Electronic Throttle Control(ETC) system is made of the components throttle body, Throttle Position Sensor(TPS)1&2 and Accelerator Position Sensor(APS) 1&2. The throttle body contains the actuator, the throttle plate and the throttle position sensor (potentiometer), which are integrated in one housing. The actuator consists of a DC motor with a two-stage gear. The opening angle of the throttle valve is detected by the throttle position sensor which is mounted on the throttle body. And it provides feedback to the ECM to control the throttle motor in order to control the throttle valve opening angle properly in response to the driving condition.

DTC Description

Checking output signals from TPS under detecting condition, if the difference between real and target throttle position is above the specified value, ECM sets P0638.

DTC Detecting Condition





Diagnostic Circuit Diagram





Signal Waveform & Data




This is a ETC motor signal waveform with acceleration.
ECM controls ETC motor(DC motor) to operate the throttle valve.
ETC motor operate and change the throttle valve position in order to open the closed throttle valve under the acceleration condition.