P0638
PowertrainElectronic Throttlehigh severityThrottle Actuator Control Range/Performance (Bank 1)
What P0638 Means
The PCM detected that the throttle actuator is not responding within the expected range. This can cause reduced power and limp mode.
Symptoms
- Reduced engine power
- Check engine light on
- Erratic or limited throttle response
Common Causes
- Faulty throttle body/actuator
- Dirty throttle plate
- Damaged throttle control wiring
- Faulty PCM
Diagnostic Steps
- Scan throttle position data
- Inspect and clean throttle body
- Test throttle actuator motor and wiring
- Perform throttle relearn or replace throttle body
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Serious DIY~$100
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✓ Autel official store
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