EGR Tube: Description and Operation

Orifice Tube Assembly:

PURPOSE
The orifice tube assembly is a section of tubing connecting the exhaust system to the intake manifold.

OPERATION
The assembly provides the flow path for the Exhaust Gas Recirculation (EGR) to the intake manifold. The internal metering orifice creates a measurable pressure drop across the Hi and REF (Low) hoses as the EGR valve opens and closes.

The pressure differential across the orifice is picked up by the Differential Pressure Feedback (DPFE) sensor which provides feedback to the Powertrain Control Module (PCM).

CONSTRUCTION
The orifice tube contains the metering orifice and two pressure pick-up tubes.