P0638

Symptoms

• The engine has entered limp mode.
• Dips and jerks when pressing the gas pedal
• Check Engine light comes on
• Unstable idle speed
• Reduced engine power and throttle response

Causes

• Throttle valve is dirty or stuck (carbon deposits, oil)
• Throttle motor malfunction
• Throttle Position Sensor (TPS) malfunction
• Damage to wiring or throttle circuit connectors
• ECU malfunction (rare)

How to Fix

1. Read all error codes and sensor data in real time
2. Clean the throttle body with a special throttle body cleaner
3. Check the throttle position sensor (TPS) signal with an oscilloscope or scanner
4. Inspect the throttle body wiring and connectors
5. Check the mechanical freedom of movement of the damper - it should move smoothly
6. If necessary, replace the throttle body assembly or adapt after cleaning

Related codes

Error P0638 by Vehicle Brand