P0299 Turbocharger / Supercharger A Underboost Condition

P0299 is a Diagnostic Trouble Code (DTC) for Turbocharger Underboost Condition. This can happen for several reasons and it is up to the mechanic to diagnose the specific cause of this code being triggered in your situation.

OBD-II Trouble Code P0299 Data Sheet

P0299 Turbocharger / Supercharger A Underboost Condition P0299 is a generic OBD-II DTC that indicates an underboost condition.

When a turbocharged or supercharged engine is running properly, the air entering the engine is under pressure, which creates most of the power that can be obtained from this great engine.

At the same time, it is known that the turbocharger is powered by exhaust coming directly from the engine, specifically to use the turbine to force air into the intake, whereas the compressors are mounted on the intake side of the engine and are usually belt powered to force much more air into the intake.

When this part of the car fails, an OBDII trouble code, P0299, will usually appear.

What does code P0299 mean?

This Diagnostic Trouble Code (DTC) is a generic transmission code, which means it applies to OBD-II vehicles that have a turbocharger or supercharger. Affected vehicle brands may include, but are not limited to, Ford, GMC, Chevy, VW, Audi, Dodge, Hyundai, BMW, Mercedes-Benz, Ram, Fiat, etc. While general, specific repair steps may vary by depending on the brand / model.

DTC P0299 refers to a condition where the PCM / ECM (powertrain / engine control module) detects that the "A" unit, separate turbocharger, or supercharger is not delivering the normal boost (pressure).

This can be due to a variety of reasons, which we will detail below. In a normally running turbocharged or supercharged engine - the air going into the engine is pressurized and this is part of what makes so much power for an engine of this size. If this code is set, you will likely notice a reduction in vehicle power. Turbochargers are powered by the exhaust leaving the engine to use the turbine to force air into the intake port. The superchargers are mounted on the intake side of the engine and are usually belt driven to force more air into the intake, with no connection to the exhaust.

In the case of Ford vehicles, this may apply: “The PCM checks the PID reading for minimum throttle inlet pressure (TIP) while the engine is running, which indicates a low pressure condition. This DTC sets when the PCM detects that the actual throttle inlet pressure is less than the desired throttle inlet pressure by 4 psi or more for 5 seconds."

In the case of VW and Audi vehicles, the definition of the code is slightly different: "Charge pressure control: control range not reached." As you might have guessed, this is just another way to detect under-gain conditions.

P0299

Typical turbocharger and related components:

Is code P0299 dangerous?

The severity of this code can range from moderate to severe. If you postpone fixing this problem, you could potentially get more extensive and costly damage.

The presence of a code P0299 can indicate some pretty serious mechanical problems, especially if left uncorrected. If any mechanical noise or handling problems are present, the vehicle should be repaired as soon as possible. If the turbocharger unit fails while the vehicle is in motion, it can result in costly engine damage.

Symptoms of code P0299

Symptoms of a P0299 trouble code may include:

• MIL Illumination (Malfunction Indicator Lamp)
• Reduced engine power, possibly in "sluggish" mode.
• Unusual engine / turbo sounds (like something is dangling)

Most likely, there will be no other symptoms.

Possible reasons

Possible causes of Turbocharger Insufficient Acceleration Code P0299 include:

• Restriction or leakage of intake (intake) air
• Defective or damaged turbocharger (seized, seized, etc.)
• Faulty boost / boost pressure sensor
• Wastegate bypass control valve (VW) defective
• Low fuel pressure condition (Isuzu)
• Stuck injector control solenoid (Isuzu)
• Defective injector control pressure sensor (ICP) (Ford)
• Low oil pressure (Ford)
• Exhaust Gas Recirculation Malfunction (Ford)
• Variable Geometry Turbocharger (VGT) Actuator (Ford)
• VGT blade sticking (Ford)

Possible Solutions P0299

First, you'll want to fix any other DTCs, if any, before diagnosing that code. Next, you'll want to search for Technical Service Bulletins (TSBs) that may be related to your engine year/make/model/configuration. TSBs are bulletins issued by a car manufacturer to provide information about known issues, usually surrounding specific trouble codes like this one. If there is a known TSB, you should start with this diagnosis as it can save you time and money.

Let's start with a visual inspection. Inspect the air intake system for cracks, loose or disconnected hoses, restrictions, blockages, etc. Repair or replace as necessary.

Check the operation of the turbocharger wastegate control valve solenoid.

If the air intake system passes the test normally, then you'll want to focus your diagnostic efforts on the boost pressure control, switch valve (blow off valve), sensors, regulators, etc. You'll actually want to address the vehicle at this point. specific detailed repair guide for specific troubleshooting steps. There are some known issues with some makes and engines, so also visit our auto repair forums here and search using your keywords. For example, if you look around you will find that the usual solution for a P0299 in a VW is to replace or repair the changeover valve or wastegate solenoid. On a GM Duramax diesel engine, this code may indicate that the turbocharger housing resonator has failed. If you have a Ford, you will need to test the wastegate control valve solenoid for proper operation.

Oddly enough, at Ford, it's like cars with EcoBoost or Powerstroke engines like the F150, Explorer, Edge, F250 / F350, and Escape. As for VW and Audi models, it could be A4, Tiguan, Golf, A5, Passat, GTI, Q5 and others. As far as Chevy and GMC are concerned, this can mostly be seen on cars equipped with Cruze, Sonic and Duramax. The information in this article is somewhat general, as each model may have its own known fix for this code. Happy renovation! If you need help, just ask for free on our forum.

The sequence of actions to eliminate the OBD2 error - P0299

• If the vehicle has another OBDII DTC, repair or fix them first, as the P0299 code may be related to another vehicle malfunction.
• Look for your vehicle's Technical Service Bulletins (TBS) and be sure to follow the on-screen instructions to resolve the OBDII trouble code.
• Inspect the air intake system for cracks and repairs, also noting any loose or disconnected hoses.
• Check that the turbocharger relief valve throttle solenoid is working properly.
• If the air intake system is working properly, diagnose the boost pressure regulator, changeover valve, sensors, regulators, etc.

To fix the P0299 OBDII DTC, the make of the car must be taken into account.

How does a mechanic diagnose a P0299 code?

• The mechanic will start by plugging a scan tool into the car's OBD-II port and checking for any codes.
• The technician will record all the freeze frame data, which will contain information about what conditions the car was in when the code was set.
• The codes will then be cleared and a test drive will be done.
• This will then be followed by a visual inspection of the turbo/supercharger system, intake system, EGR system and any other related systems.
• The scan tools will then be used to verify that the boost pressure reading is correct.
• All mechanical systems such as the turbo or supercharger itself, oil pressure and intake system will be checked for leaks or restrictions.

Common Mistakes When Diagnosing Code P0299

Mistakes can be made if all steps are not done in the proper order or not done at all. P0299 can have a wide range of symptoms and causes. Performing the diagnostic steps correctly and in the correct order is important for an accurate diagnosis.

P0299 Ford 6.0 Diesel Diagnostic and Repair Video

We found this helpful video made by a Ford Diesel Engineer with useful information about the P0299 Underboost as the code applies to a Ford 6.0L V8 Powerstroke Diesel Engine. We are not affiliated with the producer of this video, it is here for the convenience of our visitors:

P0299 lack of power and turbo sticking on a 6.0 Powerstroke F250 diesel

What repairs can fix code P0299?

• Turbine or supercharger replacement
• Intake system repair
• EGR replacement
• Boost pressure sensor replacement
• Repair of low oil pressure in the engine

Additional comments to consider regarding code P0299

When a turbocharger fails, part of the turbine can be sucked into the engine. If there is a sudden loss of power along with mechanical noise, immediately stop the vehicle in a safe place.