The Electronic Throttle Control(ETC) system consists of the throttle body, Throttle Position Sensor(TPS)1&2 and Accelerator Position Sensor(APS) 1&2. TPS1&2 are sharing the same source voltage and ground.The ECM controls the throttle motor to open and close the throttle valve. The TPS1 output voltage increases smoothly in proportion with the throttle valve opening angle after starting. TPS2 output voltage decreases in inverse proportion with the throttle valve opening angle after starting. The TPS provides feedback to the ECM to control the throttle motor in order to control the throttle valve opening angle properly in response to the driver's demands.
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.
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.
<DTC Name>
- 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
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˚ | 3.2.V | 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 |
Fig.1) Normal waveform of ETC motor with acceleration
Fig.2) Normal waveform of ETC motor with deceleration
