VGT(Variable Geometric Turbocharger) is the device which increases the efficiency of turbocharger at low rpm and lasts optimum turbo efficiency at high rpm as varying the cross sectional area through which exhaust gas passes turbocharger impeller. It relieves turbo lag at low speed and increase engine power generation.
Engine speed, APS signal, MAFS and Boost pressure sensor information is inputted to ECM.
ECM actuates vacuum diaphragm which controls exhaust gas line as controlling VGT Control solenoid valve duty to maintain optimum state of air compression.
P0234 is set when output value is out of available range(higher than maximum value) for 15 seconds.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy |
•
Signal monitoring |
•
Turbo charger
•
Intake/exhaust system clogging. | ||
Enable Conditions |
•
Engine running (Engine speed : above 2000rpm , Fuel injection quantity : 15mg/st ) | |||
Threshold Value |
•
Output value is output of available range(higher than maximum value). | |||
Diagnostic Time |
•
15000 ms | |||
Fail Safe | Fuel Cut | NO | ||
EGR Off | NO | |||
Fuel Limit | YES | |||
Check Lamp | YES | |||
VGT Control solenoid valve component resistance | VGT Control solenoid valve operating Hz | VGT Control solenoid valve operating duty |
14.7 ~ 16.1Ω (20℃) | 300Hz | 79% at idle, decreases as accelerating |
Fig.1) VGT Control solenoid valve output waveform at 79% duty. Duty decreases as boost pressure increases.
Fig.2) VGT Control solenoid valve duty decreased at acceleration.
