Boost pressure lower than reference
â–¶ How to fix
Check the air filter Check the turbo charger and the VGT/WG actuator Check for leakages in gas exchange system Check the throttle Check the boost pressure sensor
What you'll see
No driver-visible symptom recorded.
System reaction
Engine torque/power might be reduced. Black smoke might occur, visible for engines without DPF.
Diagnostic depth
Detection
Measured boost pressure is lower than the reference boost pressure for a certain time.
Possible cause
Leakage in the gas exchange system, broken VGT/WG-actuator, broken turbo charger, clogged air filter, broken throttle (unable to open), the boost pressure sensor might have an offset error.