The pressure sensor after the turbo reads a lower pressure than set at the given revs and load. The engine is not getting enough air.
Medium to high. Usually the car goes into emergency mode. If there is whistling, smoke or oil consumption, stop - it could be the turbo itself.
Turbo diesels and turbo gasoline engines. Intercooler, sleeves, turbo control, turbocharger.
What does P0299 mean
The computer controls the pressure of the turbo with a valve (wastegate) or with variable geometry of the vanes. If it commands more pressure and it doesn't come, it records P0299. The opposite case — pressure too high — is P0234.
Symptoms
- Sudden loss of power, emergency mode
- Whistling or hissing when accelerating (leaking)
- Black or blue smoke from the exhaust
- Increased oil consumption, oil in the intercooler
| Can it be driven?
Carefully to the service. If the turbo makes a metallic sound, you are either burning oil - don't drive. A damaged turbo can send metal or oil into the engine.
Common reasons
- Leak after the turbo — cracked sleeve, loose clamp, cracked intercooler. The most common reason.
- Stuck Geometry (VNT) — soot on the blades in diesels that drive a lot in the city.
- Vacuum control — burst hose, faulty solenoid or actuator.
- Clogged air filter, DPF or catalytic converter.
- Faulty pressure sensor (see P0106).
- Worn out turbo — play in the bearings, damaged vanes.
How we diagnose it
- We compare the commanded and actual pressure during a test ride.
- We pressure test the system for leaks.
- We check the vacuum, the solenoid and the stroke of the actuator.
- We check the turbo for air and oil and, if necessary, the back pressure in the exhaust.