What does this code mean?
The monitored boost is insufficient for the calibrated operating condition. This describes a control result, not proof of a failed turbocharger. Air-path restriction, control-system behavior and environmental conditions must be evaluated within the vehicle procedure. The cited GM bulletin documents an ice-related case with possible reduced power.
Sources and interpretation [1] [3]
A code identifies a detected condition, not a part that must automatically be replaced.
Before replacing a part
Record whether the fault occurs only in cold weather and compare desired with actual boost. Review the exact engine's air path and boost-control tests. A cold-weather bulletin is not evidence that every P0299 requires a turbocharger or software replacement.
Manufacturer wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
P0299Negative Pressure DeviationP0299Turbo/Super Charger UnderboostP029900Negative Pressure DeviationManufacturer communications
17Original wording in English
AUDI
Reported code forms P0299
Supersedes Technical Service Bulletin Group 01 number 08-05 dated December 22, 2008. The MIL is on. DTC P0299 (Turbo/Super Charger Underboost) is stored in the engine control module (ECM). The condition may be the…
AUDI
Reported code forms P029900
The circlip connecting the turbo wastegate actuator rod and the wastegate flap lever can fall of due to low tension of the clip. Consequently, the wastegate linkage becomes disconnected, causing MIL on and DTC P029900.
AUDI
Reported code forms P029900
The circlip connecting the turbo wastegate actuator rod and the wastegate flap lever can fall of due to low tension of the clip. Consequently, the wastegate linkage becomes disconnected, causing MIL on and DTC P029900.
AUDI
Reported code forms P029900
Under certain driving conditions, the linkage for the waste gate actuation can encounter excessive wear which leads to play at the waste gate flap. This leads to boost escaping through a loose flap, which sets DTC…
AUDI
Reported code forms P029900
Supersedes Technical Service Bulletin Group 21 number 13-16 dated July 9, 2013. The MIL is on. DTC P029900 (Negative Pressure Deviation) is stored as a static fault in the engine control module (ECM), J623 (address word…
AUDI
Reported code forms P029900
Under certain driving conditions, the linkage for the waste gate actuation can encounter excessive wear which leads to play at the waste gate flap. This leads to boost escaping through a loose flap, which sets DTC…
Check vehicle applicability
9A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
Sources and interpretation
These explanations are editorial summaries of the linked manufacturer material. PDF page numbers count from the first file page. Original publications are in English; translations are reference aids. A cited edition is not a claim that it is the manufacturer's latest instruction.
- Audi TT Quick Reference Specification Book · October 2013 ↗
Audi of America · PDF page(s) 137 ·
- 22-NA-002 · P0299/P0234 during cold or freezing temperatures ↗
General Motors · PDF page(s) 1 ·
- 2024–2025 MY OBD System Operation Summary for Gasoline Engines ↗
Ford Motor Company · PDF page(s) 86, 87 ·
Source check date · 2026-10-27
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.