P0299

DTC P0299 Turbocharger Engine Underboost

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 ECM monitors the boost pressure sensor signal for abnormal values. If the ECM detects that the sensor signal is excessively low this DTC will set. This indicates excessive low boost pressure.

Condition for Running the DTC

^ DTCs P0016 P0089 P0091 P0092 P0101 P0102 P0103 P0112 P0113 P0116 P0117 P0118 P0201 - P0204 P0237 P0238 P0261 P0264 P0267 P0270 P0335 P0336 P0401 P0403 P0404 P0405 P0406 P042E P0602 P0642 P0643 P0652 P0653 P1125 P2146-P2151 P1293 P2227 P2228 P2229 and P268A are not set.
^ The battery voltage is between 10 to 16 volts.
^ The ignition switch is ON.
^ The difference of actual mass air flow value and desired value is less than 600mg/cyl.
^ The engine speed is between 2000 to 3600 RPM and does not vary more than 100 RPM.
^ The intake air temperature is more than 14°F (-10°C).
^ The engine coolant temperature is more than 149°F (65°C).

Condition for Setting the DTC

^ The ECM detects an excessive low boost pressure for longer than 5 seconds.

Action Taken When the DTC Sets

^ The ECM illuminates the MIL when the diagnostic runs and fails. Refer to DTC Type Definitions for Action Taken When the DTC Sets - Type A.
^ The ECM limits fuel injection quantity.
^ The ECM inhibits EGR control.
^ The ECM inhibits turbocharger control.
^ The ECM inhibits DPF regeneration control.
^ The ECM inhibits cruise control.
^ The ECM inhibits PTO control.

Condition for Clearing the DTC

^ Refer to DTC Type Definitions for Condition for Clearing the MIL/DTC - Type A.

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.
^ Check for cracked air tubing that may only open during certain engine movement conditions.
^ Check the turbocharger nozzle control solenoid valve for a sticking.
^ Use a 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.
^ Fuel system problem (low fuel pressure condition) may set this DTC.

Test Description

The numbers below refer to the step number on the Circuit System Testing.

4. A skewed boost pressure sensor value (shifted to a lower pressure) can set this DTC. The Turbocharger Boost Pressure on the scan tool should read near Barometric Pressure (BARO) with the key ON and engine OFF.

5. A skewed BARO sensor value (shifted to a higher pressure) may indicate a wrong boost pressure. The BARO on the scan tool should read near surrounding barometric pressure.

Circuit/System Testing DTC P0299