Summary
P0299 means the PCM detected that the turbocharger or supercharger is producing less boost pressure than commanded. The most common causes are boost leaks in the intercooler piping (30%), a sticking or failed wastegate/boost control solenoid (25%), and a worn turbocharger (20%). Start by checking for boost leaks — a loose clamp or cracked intercooler hose is the cheapest fix and the most frequent cause.
Severity: Moderate — reduced power, but no immediate safety risk
Safe to drive: Yes, gentle driving — reduced power and possible limp mode
Repair cost: $50–$2,000 depending on cause
DIY difficulty: Moderate to Hard
What does P0299 mean?
Turbocharged and supercharged engines use a compressor to force more air into the engine, increasing power output. The PCM controls boost pressure through a wastegate (turbo) or bypass valve (supercharger), and monitors actual boost with a manifold absolute pressure (MAP) sensor or a dedicated boost pressure sensor.
P0299 is set when the PCM commands a specific boost level but the measured boost is significantly lower than expected over a sustained period. The threshold varies by manufacturer, but typically the code sets when actual boost is 3–5 PSI below the target for more than a few seconds during conditions that should produce full boost.
When this code sets, many vehicles enter a reduced power mode (limp mode) to protect the engine. You will notice a significant loss of acceleration, and the vehicle may feel sluggish, especially on hills or during highway merging. The turbo may still produce some boost, just not enough to meet the PCM's target.