Parts
$10–800
P0299 — Turbocharger Underboost
CAUTIONIs it safe to drive? The turbo isn't making the boost it should. Driveable but down on power; a boost leak or stuck wastegate that's ignored can get worse.
What P0299 means
Actual boost pressure is below the commanded target. On turbo engines this is usually a leak in the charge piping, a wastegate/actuator issue, or a sensor.
Most likely causes (in order)
- Boost / intercooler pipe leak or popped coupler
- Stuck or leaking wastegate / actuator
- Faulty boost (MAP) sensor
- Failing turbo or clogged intake
Symptoms you might notice
- Noticeable power loss
- Hesitation under load
- Sometimes a hissing leak
What to check first
Pressure-test (smoke-test) the charge pipes for leaks first — a popped coupler is common and cheap. Then check wastegate operation and the boost sensor.
Repair cost & difficulty
Labor
0.5–4 hr
Difficulty
Moderate