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P0039 Powertrain

Turbocharger/Supercharger Bypass Valve A Control Circuit Range/Performance

The wastegate or bypass valve A on the turbo/supercharger does not respond mechanically as expected to its control signal. Boost pressure deviates from target.

Affected components

  • Wastegate actuator
  • Bypass valve
  • Boost pressure sensor

Common causes

  • High likelihood: Wastegate sticking from carbon
  • Medium likelihood: Vacuum/boost line leaking
  • Medium likelihood: Wastegate actuator worn

Possible symptoms

  • Charge status indicator shows fault
  • Charging may not start or interrupts
  • Slower-than-expected charge rate

Diagnostic notes

  • The malfunction indicator lamp may illuminate
  • This code can affect emissions
  • A drive cycle may be required after repair
  • Reduced-power or limp mode may occur

Related codes

Sources

Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.

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