P0299

DTC P0299

DIAGNOSTIC INSTRUCTIONS
- Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
- Review Strategy Based Diagnosis for an overview of the diagnostic approach.
- Diagnostic Procedure Instructions provides 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 5-Volt reference circuit, and a ground on a low reference circuit. The MAP pressure sensor provides a signal voltage to the ECM, relative to pressure on the 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 kPa (4 psi) to 255 kPa (36 psi). The ECM monitors the MAP sensor, by comparing a calculated predicted value at a predetermined engine load and speed, to the actual 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.

CONDITIONS FOR CLEARING THE MIL/DTC
DTC P0299 is a Type A DTC.

DIAGNOSTIC AIDS
A MAP sensor that is stuck at BARO, or is 40 kPa lower than desired while under boost, will cause this DTC to set. Use a scan tool and compare the MAP Sensor parameters to a known good vehicle. Operate both vehicles under various conditions.

CIRCUIT/SYSTEM VERIFICATION
1. If DTCs P003A, P0045, P0698, P0699, P2563, P2564 or P2565 are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis. Diagnostic Trouble Code Descriptions
2. Verify the integrity of the entire air induction and turbocharger pipes and hoses by inspecting for the following conditions:
- Any damaged components
- Loose or improper installation
- Wet or restricted air filter
- Exhaust leaks before the turbocharger
- Exhaust restrictions after the turbocharger
3. Engine running, use a scan tool to command the TC Vane Pos. Ctrl. Solenoid ON.
4. Perform a snapshot of the engine data while slowly increasing the engine speed to 1,700 RPM, and then back to idle. Refer to Scan Tool Snapshot Procedure. Component Tests and General Diagnostics
5. Plot the snapshot and verify that the MAP sensor parameter increases smoothly as the engine speed is increased and decreased smoothly as the engine speed is returned to idle.
- If the MAP parameter plot slope is not a straight line with even RPM change, replace the MAP sensor.
6. Engine running, observe the DTC information with a scan tool. DTC P0299 should not set.
7. 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. Test the charge air cooler for leaks.
2. Test the turbocharger oil supply feed.
3. Inspect the turbocharger oil supply tube for restrictions.
- If a restriction is found, clean or replace the oil supply tube as necessary.
4. 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.
- If the charge air cooler system, the turbocharger and oil supply test normal, replace the MAP sensor.

REPAIR INSTRUCTIONS
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. 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 Procedure.
- Manifold Absolute Pressure Sensor Replacement
- Turbocharger Vane Position Sensor Replacement. Verification Tests

REPAIR VERIFICATION
Engine running, command the TC Vane Pos. Ctrl. Solenoid ON with a scan tool. Take a snapshot of the engine data while slowly increasing the engine speed to 1,700 RPM, and then back to idle. Plot the snapshot and verify that the MAP sensor parameter increases smoothly as the engine speed is increased and decreased smoothly as the engine speed is returned to idle.