P004B – Turbocharger/Supercharger Boost Control ‘B’ Circuit Range/Performance

P004B Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light)

P004B Possible Causes

Faulty boost pressure/ turbocharger position sensor,Boost pressure/ turbocharger position sensor harness is open or shorted,Boost pressure/ turbocharger position sensor circuit poor electrical connection,Faulty turbocharger/supercharger

P004B Description

The turbocharger has nozzle vane which opens and closes to control the volume of the exhaust gas flowing into the turbine. This, in turn, controls the boost pressure, when the nozzle vane moves towards the closing direction, the pressure increases. When the vane moves towards the opening direction, the pressure decreases.