LR3/Disco 3
ESM Valve
The EGR System Module (ESM) valve is located on the intake manifold with a pipe connecting the exhaust manifold to
the valve. Connection between the sensor and the harness is via a six-way connector. The ESM valve is electrically
controlled by a Pulse Width Modulated (PWM) signal. The ESM valve allows burned exhaust gas to be recirculated back
into the engine. Since exhaust gas has much less oxygen than air, it is basically inert. The exhaust gas takes the place of
air in the cylinder and reduces combustion temperature. As the combustion temperature is reduced, so are the oxides of
nitrogen (NOx) emissions.
The ESM valve has an integrated Differential Pressure Feedback-Electronic/Manifold Absolute Pressure (DPFE/MAP)
sensor. This pressure transducer monitors the pressure differential on either side of an orifice in the ESM system flow
path and then transmits that information to the ECM. The pressure drop measured across this orifice is used to estimate
the flow rate of recirculated exhaust gas. An Electronic Vacuum Regulator (EVR) is used to control the vacuum signal to
the ESM valve based on the electrical signal from the ECM. The ECM monitors the ESM level based on the feedback
from the DPFE/MAP sensor, which creates a closed loop system.
CRANKCASE VENTILATION SYSTEM
Crankcase Ventilation System Component Location
