P0299: Underboost; Dtc: P0299 - Hino Motors HINO 155 series Workshop Manual

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P0299: Underboost

Boost pressure sensor

temperature sensor

(air flow sensor built in)

Technical description

• The VNT actuator moves the nozzle vane steplessly by the LEA (Linear Electric Actuator) to control the turbo speed

and boost pressure. It compares the target boost pressure and actual boost pressure to check if the actual pressure

is lower than the target pressure.

• The boost pressure is lower than the stipulated value.

DTC set condition

DTC detection condition

• Water temperature at the engine start-up is 0 C {32 F} or above.

The conditions described below remain for 4 seconds or more.

• The target boost pressure is 40 kPa (gauge) or more.

• If the engine speed is 750 r/min, fuel injection quantity is 100 mm

• If the engine speed is in range of 1250 to 1750 r/min, fuel injection quantity is 60 mm

• If the engine speed is 2500 r/min, fuel injection quantity is 120 mm

• Atmospheric pressure is higher than 75 kPa.

• DPR auto-regeneration is not actuated.

Judgement criteria

• Deviation between the target boost pressure and the actual boost pressure: the condition that the deviation

exceeds the range of -30 to -50 kPa remains 30 seconds or more.

• If target boost pressure is 140 to 220 kPa, the deviation of boost pressure detected is -30 kPa or less.

• If target boost pressure is 220 to 250 kPa, the deviation of boost pressure detected is -40 kPa or less.

ENGINE (J05E)/TROUBLESHOOTING

Coolant temperature

pressure sensor

/st. cyl or more.

/st.cyl or more.

EN01H02127030602016066

SHTS021270300376

/st.cyl or more.

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