Error code

OBD2 P0638

OBD2P0638
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Throttle Actuator Control Range/Performance.

Severity

moderateCan drive, but may experience poor acceleration and other issues.

Summary

P0638 indicates a range or performance issue with the throttle actuator control on bank 1 of the engine. This can affect how the throttle responds during acceleration.

Symptoms

  • Poor acceleration or engine hesitation
  • Hard or no start conditions, especially when hot or cold
  • Rough idle or stalling at low speeds

Common Causes

  • Damaged wiring or connectors in the CAN bus system
  • Defective throttle actuator
  • Faulty throttle actuator position switch
  • Unauthorized performance settings causing unpredictable results

Diagnosis

  1. Record all fault codes and freeze frame data.
  2. Inspect wiring and connectors for damage or corrosion.
  3. Perform electrical tests on the throttle actuator and position switch.

Fixes

  • Replace damaged wiring, connectors, or faulty components as needed.

FAQ

Can I drive with P0638?

Yes, but driving may be difficult due to poor acceleration and other issues.

What causes P0638?

Common causes include damaged wiring or connectors in the CAN bus system, a defective throttle actuator, or a faulty position switch.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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