- Vehicles
- Cars
P0299
P0299 (generic OBD-II): turbocharger or supercharger A underboost
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
Actual boost pressure stayed below what the engine computer requested. You may notice a lack of power. Drive gently, save the codes and ask the workshop for a leak test before replacing the turbo.
Safety first
Stop and check this first
- If you notice blue smoke or a metallic turbo noise, stop stressing the engine: a damaged turbo can get worse quickly.
Safe checks you can perform
- Power loss and noises when accelerating
- Boost and sensor codes
Leave these tasks to a qualified professional
- Do not attempt this professional task: Wastegate control
- Do not attempt this professional task: Leak test and desired against actual boost
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Wastegate control
What they doThe technician checks wastegate movement and its actuator or solenoid with diagnostic equipment.
They must show youthe wastegate movement when commanded.
In writingwhether the actuator is adjusted or replaced and the boost after the repair.
Leak test and desired against actual boost
What they doThe technician pressurises the intake system to look for leaks and compares desired and actual boost during a test.
They must show youthe leak point if there is one and the desired and actual pressures during the test.
In writingthe confirmed cause and the part repaired or replaced.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Power loss and noises when accelerating
- Who:
- you, driving normally.
- How:
- notice whether the car has lost pull, whether there is a new whoosh or whistle when accelerating and whether there is smoke from the exhaust.
- Result that matters:
- which symptoms come with the code.
- If there is a whoosh when accelerating:
- tell the workshop; it points to a boost leak in the hoses.
- If there is blue smoke or a metallic turbo noise:
- do not stress the engine and book an inspection as soon as possible.
- Evidence to keep:
- a note of the symptoms and a video with sound if you can record it with the car parked.
Do not do hard acceleration tests on the road to reproduce the fault.
Evidence: Ford 2020-2023 gasoline OBD system operation
Boost and sensor codes
- Who:
- you or anyone with a generic OBD-II reader, with the engine off.
- How:
- read all codes and save the P0299 freeze frame.
- Result that matters:
- whether wastegate, boost pressure or barometric sensor codes also appear.
- If there are codes from those components:
- the workshop should start with them.
- If P0299 is alone:
- the workshop should run a leak test on the boost system.
- Evidence to keep:
- a photo of the codes and the freeze frame.
Read, photograph and unplug; do not clear anything. Watching the reader while driving distracts you, and clearing loses the snapshot of the fault conditions.
Evidence: Ford 2020-2023 gasoline OBD system operation · Title 13, California Code Regulations, Section 1968.2, Malfunction and Diagnostic System Requirements (OBD II)
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Vehicles
- Brand
- OBD-II genérico
- Product type
- Cars
Known code variants
- Ford P0299
- P0299
- P0299 baja presión turbo
- P0299 code Ford
- P0299 Ford
- P0299 OBD2
- P0299 turbo underboost
What it means
P0299 is the generic code for turbocharger or supercharger A underboost. In Ford's documentation, the computer continuously compares desired and actual boost pressure and sets the fault when the gap exceeds its limit for a few seconds. The monitor depends on the wastegate, its control, the bypass valve and barometric pressure. A hose leak, a control that does not close or a sensor can produce the same code as a damaged turbo.
Warnings and stop conditions
- Mediumeditorial warning
If you notice blue smoke or a metallic turbo noise, stop stressing the engine: a damaged turbo can get worse quickly.
Evidence: Ford 2020-2023 gasoline OBD system operation
Symptoms and causes
Probable causes · in order
- Boost air leakPossible
A loose or split hose between turbo and engine lets pressure escape. Suspect it if you hear a whoosh when accelerating; a leak test confirms it.
Evidence: Ford 2020-2023 gasoline OBD system operation
- Wastegate controlPossible
If the wastegate or its control does not close, the turbo cannot build pressure. Ford lists it among the actuators that must work for this monitor.
Evidence: Ford 2020-2023 gasoline OBD system operation
- Pressure sensor or turboPossible
A sensor that reads low or a damaged turbo complete the list. They are only confirmed after ruling out leaks and control.
Evidence: Ford 2020-2023 gasoline OBD system operation
Virtual technician
Does P0299 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Ford 2020-2023 gasoline OBD system operation
Ford Motor Company · 2023 · manual
- 2
California Air Resources Board · 2006 · official_doc
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