P0639 Throttle Actuator Control Range/Performance (Bank 2)

P0639 points to throttle actuator control range or performance on Bank 2. The Bank 2 throttle actuator response does not match the controller command.

Code details

Generic OBD-II · P0

System: Computer
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not assume both banks have the same fault; compare Bank 2 actuator response against Bank 1 data.

Symptoms of P0639

Check-engine light, sometimes with several unrelated codes at once.
Warning lights, a no-start, or intermittent electrical faults.
Communication or module-reset problems on a scan tool.

Common causes of P0639

Low battery voltage, poor grounds, corroded connectors, or blown fuses.
Wiring or network (CAN bus) faults between modules.
A module software/programming issue, or rarely a failed controller.

Useful checks before replacing parts

Compare Bank 2 commanded and actual throttle position, accelerator pedal inputs, airflow, idle behavior, freeze-frame data, and Bank 1 behavior.
Inspect Bank 2 throttle wiring, connector condition, actuator movement, carbon buildup, reference voltage, grounds, and intake restrictions.
Run the appropriate throttle test or relearn and confirm Bank 2 movement is smooth, proportional, and consistent with command.

Related OBD-II codes

These nearby computer entries can help compare wording and pin down the fault area.