P0299: Turbocharger underboost condition
What the code tells you on its own
- System
- Powertrain
- Functional group
- Turbo and boost control
- Subsystem
- Fuel and air metering
- Failure type byte, when the tool sends one
- 00 (No sub-type information)
Engine, fuel, air, ignition, emissions and transmission. The overwhelming majority of what workshops bring to the AI.
Scan tools report the same fault as P0299 and as P0299xx, where xx is a sub-type. They are one fault, and whether the sub-type appears at all depends on the tool and the protocol rather than on the car.
P0299 worked through, on a real car
Short walkthroughs of this diagnosis on a vehicle in front of us, from the code to the measurement.
What we see when P0299 turns up
Measured across the diagnostics run through Wrenchlane, not taken from a reference table. Figures as of 2026-10-06.
- Diagnostics
- 75
- Separate workshops
- 31
- Arrived code only
- 20%
- Most common marque
- Volkswagen
February 2026 to October 2026
Not one shop meeting it repeatedly
No symptom description entered at all
Where we have seen it most
These are counts from our own work, not a claim about how common the fault is across all vehicles. They describe what independent workshops brought to us, which is a narrower and more specific thing.
What P0299 usually turns up with
Measured across our own diagnostics. The multiplier is how much more often the two appear together than chance would predict, so a high number means the pair is telling you something a single code is not. Codes rarely arrive alone, and reading the set is usually faster than chasing the first one on the list.
| Code | What it is | Seen together | Versus chance |
|---|---|---|---|
| P0049 | Turbocharger turbine overspeed | 3 times | 19.2x |
| P2262 | Turbocharger boost pressure not detected, mechanical | 3 times | 19.2x |
| P00BD | Mass air flow sensor A circuit range/performance, air flow too high | 5 times | 14.2x |
| P2015 | Intake manifold runner position sensor circuit range/performance, bank 1 | 5 times | 12.8x |
| P0675 | Cylinder 5 glow plug circuit | 3 times | 12.8x |
| P2452 | Diesel particulate filter pressure sensor A circuit | 3 times | 11x |
Run P0299 against the car in front of you
Enter the code and the symptoms and get ranked probable causes for that specific vehicle, with the checks in the order worth doing them. Free account, no card.
Start freeOther turbo and boost control codes
- P2563 Turbocharger boost control position sensor circuit range/performance
- P0234 Turbocharger overboost condition
- P2279 Intake air system leak
- P2263 Turbocharger boost system performance
- P0236 Turbocharger boost sensor A circuit range/performance
- P00BD Mass air flow sensor A circuit range/performance, air flow too high
- P0245 Turbocharger wastegate solenoid A low
- P00BC Mass air flow sensor A circuit range/performance, air flow too low
FAQ
Frequently asked questions
How do I run a diagnosis?
Select the vehicle on Start, click the Diagnostic card and choose New diagnostic. Fill in the description, the error codes and the mileage, then click Analyze.
Learn more: Diagnostic (vehicle-first start), Diagnostic form: description, error codes and mileage
Do I have to type the codes from my scan tool?
No. Click the camera button next to Error codes and take or choose a photo (JPEG or PNG) of the scan tool's screen; WrenchLane reads the codes and their descriptions into the form. You can also speak them with the microphone.
Learn more: OBD reader photo scan (fault codes from a photo), Voice input for the problem description
Are the public fault code pages built from my diagnostics?
They are built from anonymised, aggregated diagnostics run in WrenchLane; no workshop, customer or vehicle can be identified. Each fault code page shows how often the code was seen across those diagnostics and in how many separate workshops.
Learn more: Fault code pages on wrenchlane.com (fault-code cluster)