Device and technical description 4.0L (Discovery 3)

Location of EGR system components

Item name	Spare part catalog number	Description
1	-	Fuel manifold damper
2	-	Vacuum control hoses
3	-	The pipe that connects the exhaust manifold to the exhaust gas recirculation (EGR) hose
4	-	Exhaust manifold
5	-	ESM valve

The exhaust emissions in the V6 gasoline engine are controlled by the engine control module (ECM). The exhaust emissions control system consists of:

• EGR system
• Crankcase Emission Reduction System

EGR system

ESM valve

The EGR control unit (ESM) valve is located on the intake manifold and is connected to the exhaust manifold by a tube. The sensor is connected to the wiring harness via a 6-pin connector. The ESM valve is controlled by an electric actuator using pulse width modulation (PWM) signals. The ESM valve allows exhaust gases to recirculate and return to the engine. Since exhaust gases contain very little free oxygen, they are virtually inert. The exhaust gases replace air in the cylinder, which reduces the combustion temperature. A decrease in combustion temperature leads to a decrease in the formation of nitrogen oxides (NOx).



The ESM valve incorporates a differential pressure/manifold absolute pressure (DPFE/MAP) electronic feedback sensor. The pressure sensor monitors the pressure difference across the diaphragm in the ESM passage and transmits this data to the ECM. The pressure difference measured across the diaphragm is used to estimate the EGR flow rate. The electronic vacuum regulator (EVR) adjusts the vacuum signal to the ESM valve based on the electrical signal from the ECM. The ECM controls the ESM level using the feedback signal from the DPFE/MAP sensor. This creates a closed-loop control system.

Engine crankcase ventilation system

Location of components of the engine crankcase ventilation system

Item name	Spare part catalog number	Description
1	-	Crankcase ventilation (CCV) hose and cam lock connector
2	-	The tube connecting the fuel vapor recovery system to the engine
3	-	Fuel Evaporative Emission System Valve
4	-	Crankcase ventilation (CCV) hose
5	-	Positive Crankcase Ventilation (PCV) Hose and PCV Valve
6	-	PCV Connecting Wire with Built-in Thermistor

Positive Crankcase Ventilation (PCV) Valve

The forced crankcase ventilation system of the engine includes:

• Positive Crankcase Ventilation (PCV) Valve
• Positive Crankcase Ventilation (PCV) Hose
• Crankcase ventilation (CCV) hose

The PCV valve is an electrically heated control valve that allows gas from the left cylinder head to flow into the air intake. Electrically heating the pCv valve allows it to remain operational in cold climates. Power for the PCV heater is supplied through the fuel pump relay. Therefore, the heater is always on while the engine is running. The current supplied is regulated inside the PCV.