P0299 Turbocharger/Supercharger Underboost

Powertrain Severity: Moderate Generic OBD-II

Boost pressure is lower than requested.

Common causes

  • Boost leak (split hose, loose clamp, intercooler)
  • Sticking wastegate or VNT vanes
  • Faulty boost control solenoid
  • Worn turbocharger

Symptoms

  • Check engine light
  • Loss of power
  • Whistling or hissing under load
  • Limp mode

What to check

  1. Pressure-test the intake for boost leaks
  2. Inspect hoses and intercooler
  3. Check actuator movement

Manufacturers may add their own detail to generic codes. If your vehicle shows a different description for P0299, follow the service information for that make and model.