Exhaust Gas Recirculation (EGR) System Module (ESM)

The ESM 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.

ESM 

Fig 1: Identifying Exhaust Gas Recirculation System Module

Courtesy of FORD MOTOR CO.