Exhaust Gas Recirculation (EGR) System Module (ESM): Notes

The ESM functions in the same manner as a conventional differential pressure feedback EGR system. The various system components have been integrated into a single component called the ESM. The flange of the valve portion of the ESM bolts directly to the intake manifold with a metal gasket that forms the metering orifice. This arrangement increases system reliability, response time, and system precision. By relocating the EGR orifice from the exhaust to the intake side of the EGR valve, the downstream pressure signal measures manifold absolute pressure. This manifold absolute pressure signal is used for EGR correction and inferred barometric pressure (BARO) at ignition ON. The system provides the PCM with a differential pressure feedback EGR signal that is identical to a traditional differential pressure feedback EGR system.