Fault Family System: Powertrain (P-Codes) 5 SAE Codes

Turbo Underboost Condition

Diagnostic & Technical Explanation

Code P0299 (Turbocharger/Supercharger A Underboost Condition) sets when boost pressure falls short of the commanded target, indicating a real mechanical underboost event rather than a sensor circuit fault. Causes are a boost leak in the charge piping, a wastegate stuck open, a worn turbocharger, or a restricted air filter.

These 5 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 5 times.

Codes in this family (5)

Code	Definition	Repair coverage
P0299	Turbocharger/Supercharger A Underboost Condition	4 ranked fixes
P02CB	Turbocharger/Supercharger B Underboost Condition	4 ranked fixes
P2262	Turbocharger/Supercharger Boost Pressure A Not Detected - Mechanical	4 ranked fixes
P2CB7	Turbocharger/Supercharger Boost Pressure B Not Detected – Mechanical	4 ranked fixes
P2D2F	Cold Start Turbocharger/Supercharger A Underboost	4 ranked fixes

What this page does not show

This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here:

Procedures 2..n after the first-listed procedure
Aftermarket parts cost ranges in USD (est_parts_cost_min/max_usd)
Professional labor-hour estimates (est_labor_hours)
Step-by-step diagnostic and repair instructions
Replacement-part mappings and catalog lookups
6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)

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