Error code · Engine

P0299 — Turbocharger/Supercharger "A" Underboost Condition

Don’t put off the repair

Open this code in the appDownload the app

A fault code doesn’t yet mean the unit or sensor itself is faulty: often it’s the plug and connector leading to it.

Possible causes

What you can do yourself

  1. Inspect the boost hoses and clamps for oil and cracks.
  2. Compare the boost under load with the norm on the “Sensors” tab.

Stop and don’t drive on if:

  • The Check Engine light is flashing
  • The temperature gauge is in the red or the overheating light is on
  • The red oil pressure light is on
  • Smoke from under the bonnet, a burning or petrol smell
  • Strong jerking, knocking from the engine, or the car barely moves

OA case from Oleg’s practice

  • Mercedes-Benz G 63 AMG 2023 Check Engine is on, but it drives as usual: P02CB00 and P029900 — low boost pressure, U115800 — left air flap. Too early to replace the turbos: first the air filters, intake and flap, then a repeat diagnosis. How it went ↗

The explanation comes from the error code reference in the AvtoElektrik PRO app.

Need a mechanic’s help?

Couldn’t fix it yourself? Oleg, an auto electrician, does computer diagnostics and repairs: he comes out anywhere in Almaty or sees you at his workshop.

Car computer diagnostics in AlmatyCall: +7 701 121 11 10

Want to figure it out yourself?

Oleg’s course “Car computer diagnostics with a scan tool”: how to hook up a scanner, read codes and live data, and use them to find the cause. The first lessons are free.

Scan tool diagnostics course →

Nearby codes

All codes in P02xx →

Who keeps this reference

The reference is kept by Oleg Dmitriev, an auto electrician from Almaty with 26 years of experience: computer diagnostics of cars and trucks, repair of control units (ECUs). Can’t find the cause? Message him.

Oleg’s auto electrician websiteWhatsApp +7 701 121 11 10