P0299: Turbocharger/Supercharger A Underboost Condition
The turbo isn't making the boost pressure the engine computer expects. Most often a boost leak.
Green, yellow, red: three ways P0299 can look
The same code can be a quick fix or a reason to pull over. Match your situation to the closest example.
Keep an eye on it
Set once pulling a hill in heat, normal power the rest of the time.
Schedule a repair
Noticeable power loss or a new whistle. Get it checked; boost leaks and sticky actuators get worse.
Stop and get help
Loud whine or grinding, heavy smoke, or oil blowing from the exhaust. Shut it down; the turbo may be failing.
Symptoms you might notice
- Loss of power
- Slow acceleration
- Whistle or hiss under load
- Black smoke (diesel)
Common causes, cheapest first
- Split charge air hose or loose clamp
- Cracked intercooler
- Wastegate or VGT actuator sticking
- Clogged air filter
- Failing turbo
- Exhaust restriction (plugged DPF on diesels)
What you can check before calling
- Listen for a new hiss under acceleration
- Check intercooler hoses for oil or looseness
- Check the air filter
A code points to a system, not a part. Replacing parts based on the code alone is how people spend money without fixing the problem. Testing confirms the cause first.
Generic codes (second character 0) mean the same thing on every vehicle. Some manufacturers add their own details, so check service information for your exact vehicle.
Related codes
More turbo & boost codes
Look up another code
Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).
Questions
What does P0299 mean?
P0299 means "Turbocharger/Supercharger A Underboost Condition". The turbo isn't making the boost pressure the engine computer expects. Most often a boost leak.
Can I drive with code P0299?
It depends on what the vehicle is doing. Green: Set once pulling a hill in heat, normal power the rest of the time. Yellow: Noticeable power loss or a new whistle. Get it checked; boost leaks and sticky actuators get worse. Red: Loud whine or grinding, heavy smoke, or oil blowing from the exhaust. Shut it down; the turbo may be failing.
What causes P0299?
The most common causes are: split charge air hose or loose clamp; cracked intercooler; wastegate or VGT actuator sticking.
Is P0299 a serious code?
It can be. Loud whine or grinding, heavy smoke, or oil blowing from the exhaust. Shut it down; the turbo may be failing.
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