Throttle Actuator Control Range/Performance (Bank 2)
P0639 indicates the throttle actuator control system on Bank 2 is not operating within the manufacturer's specified range or performance parameters. This code sets when the engine control module detects an electrical or mechanical problem preventing proper throttle blade positioning during acceleration or idle.
What You Might Notice
- Check Engine Light illuminated
- Vehicle hesitation during acceleration
- Rough idle or unstable engine speed
- Reduced fuel economy
- Difficulty maintaining constant throttle position
Most Common Causes
- 1
Throttle Actuator Motor Malfunction
The throttle actuator motor may be electrically faulty, mechanically stuck, or worn, preventing it from controlling throttle blade position properly.
- 2
Dirty or Carbon-Clogged Throttle Body
Accumulated carbon deposits inside the throttle body can restrict the throttle blade movement, causing the actuator to work outside normal parameters.
- 3
Pedal Position Sensor Malfunction
A faulty accelerator pedal position sensor can send incorrect signals to the engine control module, causing improper throttle actuator commands.
- 4
Wiring Harness or Connector Issues
Corroded, damaged, or loose wiring connections between the throttle actuator motor and the engine control module can disrupt signal transmission.
How to Diagnose It
- 1
Check Throttle Actuator Motor Malfunction — The throttle actuator motor may be electrically faulty, mechanically stuck, or worn, preventing it from controlling throttle blade position properly.
- 2
Check Dirty or Carbon-Clogged Throttle Body — Accumulated carbon deposits inside the throttle body can restrict the throttle blade movement, causing the actuator to work outside normal parameters.
- 3
Check Pedal Position Sensor Malfunction — A faulty accelerator pedal position sensor can send incorrect signals to the engine control module, causing improper throttle actuator commands.
- 4
Check Wiring Harness or Connector Issues — Corroded, damaged, or loose wiring connections between the throttle actuator motor and the engine control module can disrupt signal transmission.
How to Fix It
- 1
Clean the Throttle Body
Remove the throttle body and clean it thoroughly with carburetor cleaner to remove carbon buildup and restore proper throttle blade movement.
- 2
Inspect and Repair Wiring Connections
Check the wiring harness and connectors leading to the throttle actuator motor for corrosion, damage, or loose connections. Clean contacts or replace damaged wiring as needed.
- 3
Replace the Throttle Actuator Motor
If the motor is electrically faulty or mechanically stuck, remove and replace the throttle actuator assembly with a new or remanufactured unit.
- 4
Test and Replace Pedal Position Sensor
Use a scan tool to test the accelerator pedal position sensor output. If readings are erratic or out of range, replace the pedal position sensor.
Need a deeper diagnosis?
Search for related repair guides or browse by system.