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 PCM to control the throttle motor in order to control the throttle valve opening angle properly in response to the driving condition.
Checking output signals from TPS under detecting condition, if the difference between real and target throttle position is above the specified value, PCM sets P0638. MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till 1 driving cycle.
Item | Detecting Condition | Possible cause |
DTC Strategy | ● Detects ETS Position control problems | ● Throttle stuck ● Open in motor circuit ● Faulty motor ● Faulty PCM |
Enable Conditions | ● Engine works ● Battery voltage > 5V | |
Threshold value | Case1 | ● Rear throttle position - target throttle position > 8.8° |
Case2 | ● When real Throttle position < 44°, real throttle position - target throttle position < -8.8° | |
Case3 | ● Real throttle position - target throttle position < -22° | |
Diagnosis Time | ● Continuous (More than 0.6 seconds failure for every 15.6 seconds test ) | |
MIL On Condition | ● 1 driving cycle |
Throttle opening ( ° ) | Output voltage(V) [Vref=5.0] | Throttle opening ( ° ) | Output voltage(V) [Vref=5.0] | ||
TPS1 | TPS2 | TPS1 | TPS2 | ||
0° | 0.0V | 5.0V | 60° | 2.7V | 2.3V |
10° | 0.5V | 4.5V | 70° | 3.2V | 1.8V |
20° | 0.9V | 4.1V | 80° | 3.6V | 1.4V |
30° | 1.4V | 3.6V | 90° | 4.1V | 0.9V |
40° | 1.8V | 3.2V | 100° | 4.5V | 0.5V |
50° | 2.3V | 2.7V | 110° | 5.0V | 0.0V |
