P0299

DTC P0299

Circuit Description
The boost pressure sensor is located in the air induction tubing. The sensor is a transducer that varies voltage according to changes in the air pressure inside the air tubing. The engine control module (ECM) monitors the boost pressure sensor signal for abnormal values. If the ECM detects that the boost pressure sensor signal is excessively low, this DTC will set.

Condition for Running the DTC
- Accelerator pedal position is more than 80%.
- Engine speed is between 2000-2900 RPM.
- DTC P0237, P0238, P2228 or P2229 is not set.

Condition for Setting the DTC
- Relative boost pressure is less than 1 psi (5 kPa) for 5 seconds.

Action Taken When the DTC Sets
- The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records.
- The ECM limits accelerator control range within 40%.
- The ECM closes the EGR valve and holds to close position.
- The ECM inhibits cruise control.
- The ECM inhibits PTO control.

Condition for Clearing the DTC
- A current DTC, clears when the ignition is turned OFF.
- Clear the MIL and the DTC with a scan tool.

Diagnostic Aids
- Induction air leakage can cause a low boost pressure condition. A whistling noise may be heard if a component is allowing air to enter the induction system. Close the throttle plate, remove the boost pressure sensor and introduce shop air into the line. Feel around the air tubing for leaks.
- Check for cracked air tubing that may only open during certain engine movement conditions.
- Check the waste gate for a sticking or stuck open condition. Refer to Waste Gate Operation in the Engine Mechanical section.
- Use the scan tool to verify the integrity of the boost pressure sensor signal. Compare the sensor values under all load conditions for an excessively low value. Use the scan tool data list values for nominal sensor readings.

Test Description
The numbers below refer to the step number on the diagnostic table.
3. A skewed boost pressure sensor value (shifted to a low pressure) can set this DTC. The Boost Pressure on the scan tool should read nearly barometric pressure with the key ON and engine OFF.
4. A skewed barometric pressure (BARO) sensor value shifted to a higher pressure) can set this DTC. The BARO on the scan tool should read nearly surrounding barometric pressure.

DTC P0299

Schematic Reference: Engine Controls Schematics

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