The purpose of the EGR system is to reduce certain emissions and certain engine speeds and temperatures. The down side is a reduction in performance and economy and the carbon build up with higher mileage vehicles.
Most car manufacturers now fit EGR devices on their vehicles, they all to some certain extent cause problems on older vehicles. The Land Rover TD5 EGR system is particularly troublesome and is best done away with.
EGR kits are one of the easiest modifications you can do if you’re a competent DIY mechanic. Benefits are it can lower engine temperatures, improve throttle response and provide better MPG, reducing smoke and carbon deposits.
The EGR valve is controlled by the ECU and is operated by 1 or 2 small vacuum pipes depending on the year, controlled by either 1 or 2 solenoids. The small vacuum pipes connecting to the EGR valve can be removed and the connections on the solenoid blanked off with the supplied rubber blanking plugs. The ECU continues to think that there is an EGR system fitted and will not throw up a fault code.