P0638 — Throttle Actuator Control Range/Performance Bank 1

P0638: Throttle Actuator Control Range/Performance Bank 1 — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Throttle Actuator Control Range/Performance Bank 1. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Powertrain

Symptoms

  • Unstable idle; delayed acceleration and reduced power.

Possible causes

  • Faulty actuator, stuck/dirty throttle or damaged connections.

What to check

  • Inspect throttle connections and deposits; check battery condition.

Also written as: P0638-00, P063800, PO638 (some scan tools add the fault-type byte, e.g. -00).