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
- DTCs P0016, P0089, P0091, P0092, P0101, P0102, P0103, P0112, P0113, P0116, P0117, P0118, P0201, P0202, P0203, P0204, P0237, P0238, P0261, P0264, P0267, P0270, P0335, P0336, P0401, P0403, P0404, P0405, P0406, P0478, P0602, P0642, P0643, P1125, P1293, P1404, P2146, P2147, P2148 P2149, P2150, P2151, P2227, P2228 and P2229 are not set.
- The battery voltage is between 10-16 volts.
- The ignition switch is ON.
- The accumulation fuel injection quantity is more than 100 cu.mm.
- The actual mass air flow is higher than desired by 600 mg/cyl.

AND following conditions are met longer than 3 seconds.
- The engine speed is between 2000-3600 RPM.
- The engine speed does not vary more than 100 RPM.
- The fuel injection quantity is less than 300 cu.mm.
- The fuel injection quantity does not vary more than 10 cu.mm.
- The intake air temperature is higher than 50 °F (10 °C).
- The coolant temperature is higher than 149 °F (65 °C).

Condition for Setting the DTC
- The ECM detects excessive low boost pressure for longer than 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 Freeze Frame/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 MIL/DTC
- The ECM turns OFF the MIL after 3 consecutive driving cycles when the diagnostic runs and does not fail. (12,000 lbs GVW)
- The ECM turns OFF the MIL when the diagnostic runs and does not fail. (Except 12,000 lbs GVW)
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes after the key is cycled.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic after the ECM turns OFF the MIL.
- 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 near 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 near surrounding barometric pressure.

DTC P0299
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views

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