OPERATION x ).
The Exhaust Gas Recirculation (EGR) system is designed to reintroduce exhaust gas into the combustion chambers, thereby lowering combustion temperatures and reducing the formation of Oxides of Nitrogen (NO
The amount of exhaust gas that is reintroduced into the combustion cycle is determined by several factors, such as: engine speed, engine vacuum, exhaust system backpressure, coolant temperature, throttle position. All EGR valves are vacuum operated. The EGR vacuum diagram for your particular vehicle is displayed on the Vehicle Emission Control Information (VECI) label.
The EGR system is Differential Pressure Feedback EGR (DPFE) system is controlled by the Powertrain Control Module (PCM).
COMPONENT TESTING EGR Valve
- Install a tachometer on the engine, following the manufacturer's instructions.
- Detach the engine wiring harness connector from the Idle Air Control (IAC) solenoid.
- Disconnect and plug the vacuum supply hose from the EGR valve.
- Start the engine, then apply the parking brake, block the rear wheels and position the transaxle in Neutral.
- Observe and note the idle speed.
If the engine will not idle with the IAC solenoid disconnected, provide an air bypass to the engine by slightly opening the throttle plate or by creating an intake vacuum leak. Do not allow the idle speed to exceed typical idle rpm.
Using a hand-held vacuum pump, slowly apply 5-10 in. Hg (17-34 kPa) of vacuum to the EGR valve nipple, and compare the results with the following:
- If the idle speed drops more than 100 rpm with the vacuum applied and returns to normal after the vacuum is removed, the EGR valve is OK.
- If the idle speed does not drop more than 100 rpm with the vacuum applied and return to normal after the vacuum is removed, inspect the EGR valve for a blockage; clean it if a blockage is found. Replace the EGR valve if no blockage is found, or if cleaning the valve does not remedy the malfunction.
REMOVAL & INSTALLATION EGR Valve
- Disconnect the negative battery cable.
- On Legend, remove the EGR lift sensor electrical connector.
- Disconnect the vacuum hose from the EGR valve.
- Remove the EGR valve mounting fasteners, then separate the valve from the intake manifold.
- Remove and discard the old EGR valve gasket, and clean the gasket mating surfaces on the valve and the intake manifold.
- Install the EGR valve, along with a new gasket, on the upper intake manifold, then install and tighten the mounting bolts
- Attach the vacuum hose to the EGR valve.
- Connect the negative battery cable.
EGR Valve Solenoid
- Locate the EGR solenoid.
- Remove the vacuum lines and wiring connectors.
- Unfasten the mounting screws, then remove the solenoid by lifting it off.
- Install the solenoid and secure with the mounting screws.
- Attach all disconnected vacuum lines and wiring connectors.