P0299 — Turbocharger/Supercharger Underboost

P0299 means the engine produced less boost than commanded. Boost leaks in the charge pipes are by far the most common cause, followed by a sticking wastegate or VNT actuator.

Cost range: $50–$2,500. Severity: medium. Safe to drive? Yes but expect limp mode and heavily reduced power. Persistent underboost can indicate turbo damage.

Most common causes of P0299

1. Boost leak in charge piping — Split hose or popped-off coupler — pressure-test the intake tract first. ($50–$300)
2. Sticking wastegate or VNT vanes — Carbon buildup on diesel variable-geometry turbos. ($200–$900)
3. Failed boost pressure sensor — Reports low even when boost is normal. ($80–$250)
4. Worn turbocharger — Shaft play or damaged wheel means replacement. ($1,200–$2,500)

Symptoms drivers report with P0299

• Sluggish acceleration
• Limp mode
• Whistling from engine bay
• Black smoke on diesels