P0299 code meaning
Turbocharger/Supercharger A Underboost Condition
Powertrain system Generic code P02xx codes Check engine light
What P0299 means
P0299 means actual boost stays below target for a period although the control already demands more. Thresholds: GM gasoline 30–55 kPa below target with the warning light in the first trip; GM diesels 10–50 kPa, two trips; Ford EcoBoost more than 4 psi (about 28 kPa) for 5 s with the wastegate already commanded fully closed; Ford diesels 30–40 kPa for 10–15 s, with a further underboost code P2263. Typical causes from manufacturer bulletins: a charge air leak, a wastegate that lost its preload or whose rod came off, a leaking bypass valve, sticking turbo vanes on diesels, and ice in the charge air cooler in winter. A faulty boost sensor can also fake underboost. Many engines then limit power.
P0299 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 6 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0299
- Loss of power, sluggish acceleration
- Limp mode, power limited
- Check engine light on
- Whistling or hissing from the charge air path under load
Common causes of P0299
- Most likelyLeak in the charge air path (hose off or torn, cooler leaking, clamps)
- Most likelyWastegate faulty (rod off, preload lost, vacuum or solenoid, diaphragm)
- PossibleTurbo vanes sticking or turbo worn (diesel)
- PossibleBypass valve leaking (torn diaphragm) or its control
- Less likelyIce in the charge air cooler, boost sensor or connector, or software
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
TurbochargerWastegateCharge air hosesBoost pressure sensor a
What each part of P0299 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 2 | Area: fuel and air metering (injector circuit). |
| 99 | The exact fault in that area. |
What to do next
- Note P0299 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0299
What does P0299 mean?
P0299 means "Turbocharger/Supercharger A Underboost Condition". P0299 means actual boost stays below target for a period although the control already demands more. It is a generic code, so it means the same on every make.
Is it safe to drive with P0299?
Drive gently and only to a workshop. With P0299 the car can go into limp mode (reduced power) to protect itself.
Will P0299 fail an emissions test?
Yes, it can. P0299 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0299 to fix?
Difficulty: medium. A typical repair takes 0.5 to 6 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0299 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.