KustomCode Logo

Powertrain fault code

P0299: Turbocharger/Supercharger "A" Underboost Condition

Fix soon

The car may go into limp mode with reduced power. Drive gently and have it checked soon.

What P0299 means

The turbo or supercharger is making less boost than the engine computer asked for.

Common causes

  • Boost leak (split intercooler hose or loose clamp)
  • Sticking turbo wastegate or vanes
  • Faulty boost pressure sensor
  • Worn turbo

What to check first

  1. Check intercooler hoses and clamps for splits or oil.
  2. Compare requested and actual boost on a live scan.

Get P0299 explained for your car: $2.99

  • P0299 explained in full for your make and model: meaning, how urgent, likely causes and what to check, in order.
  • A short personal note from us within 24 hours, or your money back.
  • Your own private report page you can save as a PDF or show your mechanic.

Read your car's codes yourself, free

Plug a cheap ELM327 OBD-II adapter into the port under the dashboard and open the scan tool: Chrome or Edge on a computer with a USB adapter, or Chrome on Android with a Bluetooth LE adapter. It reads and clears codes and shows emissions readiness. It does not work on iPhone.

Open the free scan tool

Need help with P0299?

Tell us your car and what it is doing with P0299. We reply by email with what to check first, in plain words. Free.

General guidance only, not a diagnosis. A qualified mechanic should confirm the cause before you replace parts.