Diesel Trouble Codes

P0299 — Turbocharger/Supercharger Underboost Condition — 6.7 Powerstroke

P0299 on 6.7 Powerstroke means boost pressure is below the minimum expected for current conditions.

Updated October 15, 2026

What it means

The PCM sees actual boost lower than desired under load, often triggering limp and reduced power.1

Most likely causes

  1. Charge-air-cooler (intercooler) boot leaks — Boost leaks at intercooler boots/pipes reduce measured boost; typical on this platform.1
  2. VGT vanes stuck open — VGT vanes stuck open lower boost; typical on this platform.1
  3. Sticking turbo actuator — A sticking or faulty VGT actuator can cause underboost; typical on this platform.1
  4. Restricted air filter — A restricted air filter limits inlet flow and can cause underboost; typical on this platform.1
  5. VGT vane sticking from soot — VGT vane sticking from soot is a known boost-performance issue on this platform.2
  6. Turbo actuator fault — Turbo actuator fault can cause actual boost to not track desired boost.2
  7. MAP/boost sensor error — A MAP/boost sensor error can cause underboost detection.2
  8. Turbo actuator learned travel out of range — Actuator learned travel outside allowable range indicates sticking VGT or worn/failed actuator.3

How to diagnose

  1. Verify freeze frame and repeat under load to confirm underboost.
  2. Inspect intake and charge-air system for leaks, damaged or loose intercooler boots.
  3. Check air filter restriction and intake restriction.
  4. Monitor desired vs actual boost and VGT duty cycle with scan tool.
  5. Check MAP/boost sensor readings for plausibility and wiring.
  6. Perform VGT actuator functional test and relearn if supported; note learned travel limits.
  7. Inspect turbocharger for shaft play, vane sticking, and soot buildup.

Common mistake to avoid

Replacing the turbo before smoke-testing the intake. Boost leaks at intercooler boots, end tanks and clamps are a common cause of low power and underboost codes, and they mimic a failing turbo. Source: BD Diesel — 6.7L Power Stroke problems and real fixes.

Parts and tools you may need

Tools you’ll need

Rough cost and difficulty

Likely repairPartsShop laborWho usually does it
MAP/boost pressure sensor$40–$2000.3–1 hrsEasy DIY
Intercooler boot, clamp or pipe repair$20–$2000.5–2 hrsEasy DIY
Electronic VGT actuator$400–$9001–3 hrsDIY with tools and a manual

Typical US independent-shop figures; labor runs about $120–$180 per hour (dealers charge more). Confirm the diagnosis before buying parts.

When to see a pro

If VGT mechanism is sticking, actuator is faulty, or turbocharger inspection is needed, have a qualified diesel technician evaluate and service the turbocharger system.

Check for recalls

Recalls are tied to your truck’s VIN, so check yours directly: enter the VIN at NHTSA’s recall lookup. Open safety recalls are repaired free at a dealer.

Sources

  1. Curated DTC seed — 6.7 Powerstroke (curated) ↩︎ ↩︎ ↩︎ ↩︎ ↩︎

  2. Curated DTC seed — 6.7 Powerstroke (curated) ↩︎ ↩︎ ↩︎

  3. Curated DTC seed — 6.7 Powerstroke (curated) ↩︎

Repair videos: P0299 on the 6.7 Power Stroke

Third-party videos, not ours — picked for this engine. Confirm anything against the factory service information for your truck.

6.7 Powerstroke Low Power - Low Boost - Engine Light FIX — DanielJaegerFilms · 92K views

GOT No Boost? 6.7 Ford Turbo PROBLEMS | Find out why! #mechanic #diesel — PowerStroke Tech Talk w/ARod · 21K views