DIAGNOSING, REMOVING AND REPLACING ELECTRIC EGR VALVES
A1
Before you crack open your toolbox, spend time diagnosing whether, or not, the EGR system is to blame. Start with visual checks, prior to interrogating the car’s ECU for fault codes by plugging test equipment into the OBD socket.
A2
After you have read and reset any fault codes, take the car for a drive to see if any of them return. If possible, perform any EGR actuation tests with your diagnostic equipment – follow the instructions carefully.
A3
Do not rely only on diagnostic kit – your eyes and ears are just as important. On pneumatic valves, rubber vacuum pipes split with age (arrowed bottom) and electrical connections (arrowed top) suffer from vibration, heat and water ingress.
A4
If you are certain that the EGR valve is faulty, identifying it is not always easy. Look for a connection between the exhaust and intake manifolds. This valve is in a fairly accessible position whereas…
A5
…this one is traced by following the EGR pipe from the inlet manifold to the back of the engine. This valve is not in a very convenient location (indicated). Ease of access should be a factor in whether you wish to clean or replace it.
A6
Assess if any ancillary components need removing, such as vacuum connections or an EGR pipe (pictured). Ensure that you research this beforehand and buy any replacement parts necessary for the job (see Step A11).
A7
If your car is fitted with an EGR pipe and you find that it is clogged, suspect that the EGR valve, its cooler and the intake manifold and inlet tracts/valves in the cylinderhead will be contaminated as well. (Photo courtesy of Terraclean)
A8
In most cases, the EGR valve is held in place by several nuts. Disconnect the electrical/vacuum connections before undoing the bolts and associated gaskets and lifting the valve clear.
A9
If you suspect that the EGR cooler or its bypass valve is faulty, you will have to remove the entire system as one assembly, which will mean draining the cooling system. Pictured is an EGR system on a 2008 BMW six-cylinder diesel application.
A10
Buy a replacement EGR valve that is designed for your vehicle from a reputable brand and supplier. Several garages have advised us that copy EGR valves are a false economy – stick to original equipment quality items only.
A11
Ensure you have replacement fixings for not only the EGR valve, but also ancillary parts, such as gaskets for EGR pipes, and tighten the fixings to the required torque.
A12
If a new EGR valve has been fitted, many cars will need the part to be programmed to the engine ECU. Follow the instructions provided by your diagnostic equipment carefully.