PCM monitors output signal from TPS. If the difference between real and target throttle position is above the specified value, the PCM sets a P0638 DTC and illuminates the Malfunction Indicator Lamp (MIL).
Comparing real intake air flow and the intake air flow calculated by ETS, if the air flow is more than threshold value for more than 19 seconds the PCM sets a P0638 DTC.
Item | Detecting Condition | Possible cause | |
DTC Strategy | Case1 |
•
Monitor the throttle position | (Case1) 1. Throttle stuck 2. Open in motor circuit 3. Faulty motor 4. Faulty PCM (Case2) 5. Air Leakage between TPS and MAP 6. Faulty throttle body or intake manifold 7. Faulty MAPS |
Case2 |
•
Monitor the measured engine airflow and the estimated airflow | ||
Enable Conditions | Case1 |
•
Engine running
•
No faults present | |
Case2 |
•
Engine running
•
Battery voltage greater than 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) less than - 4.5°
•
(the real throttle position - the target throttle position) less than - 18° | |
Case2 |
•
MAPS reading - ETC estimated airflow greater than 9 g/s | ||
Diagnosis Time |
•
Continuous | ||
MIL On Condition |
•
1 driving cycle | ||
※ If the Main relay is inoperable with engine running, the following DTCs can set.
<DTC Name>
- P0638 Throttle Actuator Control Range/Performance(Bank 1)
- P0685 PCM/PCM Power Relay Control Circuit /Open
- P1295 Throttle Actuator Control System - Power Management
- P2106 Throttle Actuator Control System - Forced Limited Power
