P0299: Turbocharger/Supercharger A Underboost Condition
What Does P0299 Mean?
P0299 is a diagnostic trouble code indicating: Turbocharger/Supercharger A Underboost Condition. This code relates to the fuel injection system. It has been reported in NHTSA complaints across 16 different vehicle models.
Symptoms of P0299
- ⚠️ Check engine light illuminated
- ⚠️ Poor fuel economy
- ⚠️ Engine misfires
- ⚠️ Loss of engine power
- ⚠️ Sluggish acceleration
- ⚠️ Jerking or surging while driving
Common Causes
- 🔍 Worn or fouled spark plugs
- 🔍 Clogged or leaking fuel injector
- 🔍 Throttle body or throttle position sensor issue
- 🔍 Dirty or failed MAF sensor
- 🔍 Stuck or failed EGR valve
- 🔍 Vacuum leak in intake system
P0299 Reports by Year
Real Owner Reports
From NHTSA complaint database — actual owner descriptions.
"MY CAR RANDOMLY LOST POWER IN THE MIDDLE OF THE FREEWAY FORCING ME TO TURN ON HAZARDS AND MAKE MY WAY FROM THE EXPRESS LANE TO THE NEAREST OFF RAMP GOING 20 MPH WHILE TRYING TO AVOID AN ACCIDENT. MY CHECK ENGINE LIGHT BEGAN TO FLASH RAPIDLY CAUSING FURTHER ANXIETY. FORTUNATELY I WAS ABLE TO MAKE MY "
— Honda Civic owner, 09/02/2020
"While accelerating uphill approximately 65 mph the car suddenly started to shutter and slow down to 35 mph. I forced me to move rapidly over to the right lane on a busy highway almost getting hit by a semi truck. Luckily I was able move to the shoulder and park the vehicle. I shut the vehicle off an"
— Honda Accord owner, 06/13/2025
"Scanned for codes. Found P0303, P0299, and P2243 stored. Found coolant entering cylinder 3. Found excessive play in the waste gate rod and found A/F sensor is not responding. Needs head gasket. Vehicle starts up and runs rough. All alerts on alerts on dash on cust states check engine light on. Honda"
— Honda Accord owner, 02/17/2025
Source: NHTSA Complaints Database
Most Reported Vehicles for P0299
Based on NHTSA owner complaint data.
| # | Vehicle | Reports |
|---|---|---|
| 1 | FORD ESCAPE | |
| 2 | CHEVROLET EQUINOX | |
| 3 | CHEVROLET CRUZE | |
| 4 | CHEVROLET MALIBU | |
| 5 | HONDA ACCORD | |
| 6 | HONDA CR-V | |
| 7 | FORD FOCUS | |
| 8 | FORD EDGE | |
| 9 | GMC TERRAIN | |
| 10 | DODGE DART | |
| 11 | VOLKSWAGEN JETTA | |
| 12 | VOLKSWAGEN PASSAT | |
| 13 | HONDA CIVIC | |
| 14 | FORD EXPLORER | |
| 15 | FORD FUSION |
P0299 Reports by Vehicle
Detailed NHTSA complaint analysis for each vehicle model.
Diagnostic Tips
- Scan all modules, save freeze-frame data, and clear unrelated history codes before focusing on P0299.
- Confirm whether companion codes are present first; they often identify the root cause sooner than the headline DTC.
- Prioritize inspection around engine and the most common failure path for this code family.
- Measure fuel pressure/trim behavior at idle and under load; confirm pump output and injector balance before replacing parts.
- After each repair step, complete one drive cycle and verify readiness monitors instead of judging success after a quick idle test.
- If the code keeps returning on high-incidence platforms (for example FORD ESCAPE), check TSB patterns and wiring/connector fitment before major part replacement.
Common Mistakes to Avoid
- ❌ Skipping freeze-frame review and losing the exact RPM/load conditions when the fault set.
- ❌ Replacing the fuel pump based on one reading without load testing pressure and checking trim data.
- ❌ Clearing P0299 and returning the car before monitors complete — this often creates repeat visits.
- ❌ Treating intermittent wiring or connector faults as permanent component failure without wiggle testing.
Frequently Asked Questions
Can I drive with this code?
Will this code clear itself?
How do I find the exact cause?
Reported Repair Costs for P0299
Based on 4 owner-reported repair costs from NHTSA complaints.
⚠️ These are owner-reported costs, not estimates. Actual costs vary by location, labor rates, and root cause. Source: NHTSA complaints database.
What To Do Next
Possible Fixes
- 🔧 Have the code scanned with a professional-grade scanner to read freeze frame data
- 🔧 Test the relevant sensor(s) with a multimeter before replacing
- 🔧 If DIY repair isn't feasible, get a diagnostic from a trusted mechanic ($50-150)
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1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
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Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.