P0299

DTC P0299

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provide an overview of each diagnostic category.

DTC Descriptor

DTC P0299
- Turbocharger Engine Underboost

Circuit/System Description

The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by turbocharger output, engine speed, accelerator pedal input, ambient air temperature, and barometric pressure (BARO). A diaphragm within the MAP pressure sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates these changes into electrical resistance. The MAP pressure sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts on the 5-volt reference circuit and a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to pressures, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value. Under normal operation, the lowest pressure that can exist in the intake manifold is equal to the BARO. This occurs when the vehicle is operated at idle or when the ignition is ON while the engine is OFF. The highest manifold pressures occur when the turbocharger output is high. Manifold pressure can range from 58 kPa (8 psi) when pressures are low to more than 240 kPa (34 psi) when pressures are high, depending on the BARO. The MAP pressure sensor has a range of 33-255 kPa (4-36 psi). The ECM monitors the MAP sensor by comparing a calculated predicted value at a predetermined engine load and speed, to the actual sensor input.

Conditions for Running the DTC

* DTC P2564 or P2565 is not set.
* The engine speed is between 800-3,000 RPM.
* DTC P0299 runs continuously when the above conditions are met.

Conditions for Setting the DTC

The measured MAP pressure is more than 39 kPa below the expected range for 10 seconds.

Action Taken When the DTC Sets

* DTC P0299 is a Type A DTC.
* A message center or an indicator may display reduced engine power.
* The control module commands reduced engine power.

Conditions for Clearing the DTC

DTC P0299 is a Type A DTC.

Diagnostic Aids

* If the condition is intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. and Inducing Intermittent Fault Conditions. Component Tests and General Diagnostics
* A MAP sensor that is stuck at BARO, or is skewed 40 kPa lower than desired while under boost will cause this DTC to set.
* If the vehicle passes the Circuit/System Verification Test, operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records list.

Circuit/System Verification

1. Verify that DTCs P003A, P0047, P0048, P046C, P0402, P0403, P0698, P0699, P2563, P2564 or P2565 are not set.

• If any of the DTCs are set, Refer to Diagnostic Trouble Code (DTC) List - Vehicle. Diagnostic Trouble Code Descriptions

2. Engine running, command the TC Vane Pos. Ctrl. Solenoid ON, while performing a snapshot of the induction data list. Perform the following actions during the snapshot: Refer to Scan Tool Snapshot Procedure.

* Slowly increase the engine speed to 1,700 RPM for 5 seconds and then return the engine speed to idle.
* Plot the snapshot and verify that the MAP sensor parameter increases smoothly and follows the Engine Speed parameter as the engine speed is increased, and then returned to idle

• If the MAP parameter plot slope is not a straight line with even the RPM change, replace the MAP sensor.

3. Engine running, observe the DTC information with a scan tool. DTC P0299 should not set.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame Records data.

Circuit/System Testing

1. Verify the integrity of the air induction system, the turbocharger ducts and hoses by inspecting for the following conditions:

* Any damaged components
* Any loose or improperly installed components
* Any wet or restricted air filter
* Any exhaust leaks before the turbocharger
* Any exhaust restrictions after the turbocharger
* Any snow or ice build-up in cold climates at the air cleaner and MAP sensor

2. Test the charge air cooler for leaks.
3. Test the turbocharger oil supply feed.
4. Inspect the turbocharger oil supply tube for restrictions.

• If a restriction is found, clean or replace the oil supply tube as necessary.

5. Inspect the turbocharger for debris, worn impeller and turbine blades, or damage.

• If worn or damaged turbocharger blades or vanes are found, replace the turbocharger assembly.

6. If the induction system, charger air cooler system, the turbocharger, and the turbocharger oil supply test normal, replace the MAP sensor.

Repair Instructions

If any service has been performed on the turbocharger or on the turbocharger components, a turbocharger relearn must be performed. Failure to perform the turbocharger learn procedure may cause this DTC to set. Refer to Turbocharger Learn. Programming and Relearning

Notice: After performing the system repair, perform the following:

* A code clear with a scan tool, regardless of whether or not a DTC is set

* A Diesel Particulate Filter (DPF) Service Regeneration with a scan tool

Perform the above in order to remove soot from the DPF and avoid possible DPF failure.

* Exhaust Particulate Filter Cleaning (DPF Service Regeneration) Exhaust Particulate Filter Cleaning (DPF Regeneration Enable) for exhaust particulate cleaning
* Manifold Absolute Pressure Sensor Replacement
* Turbocharger Replacement (LLY, LBZ) Turbocharger Replacement (LMM)
* Turbocharger Oil Feed Pipe Replacement

Repair Verification

Engine running, command the TC Vane Pos. Ctrl. Solenoid ON, while performing a snapshot of the induction data list. Perform the following actions during the snapshot: Refer to Scan Tool Snapshot Procedure. Component Tests and General Diagnostics

* Slowly increase the engine speed to 1,700 RPM for 5 seconds and then return the engine speed to idle.
* Plot the snapshot and verify that the MAP sensor parameter increases smoothly and follows the Engine Speed parameter as the engine speed is increased, and then returned to idle.