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 and then MIL(Malfunction Indication Lamp) turns on.
Comparing real intake air flow and the intake air flow calculated by ETS under detecting condition, if the air flow more than threshold value is detected for more than 19 sec., ECM sets P0638.
DTC Detecting Condition
Item | Detecting Condition | Possible cause |
DTC Strategy | Case1 | Monitor the throttle position
| (Case1) Throttle stuck
Open in motor circuit
Faulty motor
Faulty ECM
(Case2) Air Leakage between TPS and MAP
Faulty throttle body or intake manifold
Faulty MAPS
|
Case2 | Monitor the measured engine airflow and the estimated airflow
|
Enable Conditions | Case1 | Engine running
No faults present
|
Case2 | Engine works
Battery voltage >5V
|
Threshold value | Case1 | The difference between the real ETS motor & TPS value and the target ETS motor & TPS value is over 4.5°.
When real Throttle position is below 36°, (the real throttle position - the target throttle position) < - 4.5°
(the real throttle position - the target throttle position) < - 18°
|
Case2 | MAPS reading - ETC estimated airflow > 9 g/s
|
Diagnosis Time | Continuous
|
MIL On Condition | 1 driving cycle
|
? If Main relay has a fault(ex. Open) under engine running, the DTCs, P0638/P0685/P1295/P2106, can happen at the same time.
- P0638 Throttle Actuator Control Range/Performance(Bank 1)
- P0685 ECM/ECM Power Relay Control Circuit /Open
- P1295 Throttle Actuator Control System - Power Management
- P2106 Throttle Actuator Control System - Forced Limited Power
Specification
TPS |
Throttle Opening (°) | Output Voltage (V) [Vref=5.0] |
TPS1 | TPS2 |
0° | 0.0V | 5.0V |
10° | 0.5V | 4.5V |
20° | 0.9V | 4.1V |
30° | 1.4V | 3.6V |
40° | 1.8V | 3.2V |
50° | 2.3V | 2.7V |
60° | 2.7V | 2.3V |
70° | 3.2V | 1.8V |
80° | 3.6V | 1.4V |
90° | 4.1V | 0.9V |
100° | 4.5V | 0.5V |
110° | 5.0V | 0.0V |
MAP |
Pressure(kPa) | Voltage(V) |
20 | 0.79 |
46.66 | 1.84 |
101.32 | 4.0 |
Diagnostic Circuit Diagram
Signal Waveform & Data
Fig.1) Normal waveform of ETC motor with acceleration
Fig.2) Normal waveform of ETC motor with deceleration