MCC/Smart City Coupe/Cabrio Exhaust pressure control valve replacement

When do MCC/Smart City Coupe/Cabrio exhaust pressure control valves need to be replaced?

The exhaust pressure control valve is part of your MCC/Smart City Coupe/Cabrio's EGR system, The EGR or exhaust gas recirculation system is part of the emission control system which is designed to recirculate the exhaust gases back into the engine when the correct conditions are met, this reduces cylinder temperatures and in turn, improves emissions. This is where the exhaust pressure control valve comes in, its primary purpose is to detect the changes in the pressure of the exhaust and control the flow through the EGR system. They are commonly found on vehicles equipped with turbo-diesel engines, however, they can also be found on the EGR system of petrol engines as well.

When the exhaust pressure control valve fails or has an issue, it can cause problems with the operation of the EGR system, and even affect the engine performance. Usually, a problem with the exhaust pressure control valve will produce a few symptoms that can alert the driver of a potential issue.

The most common signs that your exhaust pressure control valve is failing are:-

1. Check Engine Light comes on

Generally one of the first symptoms is the check engine light, if your PCM detects an issue in the EGR circuit with the signal or the position of the flap it will cause the light to come on.

2. Decrease in power

If for some reason the engine light doesn't alert you to the issue you may start to notice a decrease in power, a lack of acceleration or a decrease in fuel economy

3. Excessive smoke or soot from the MCC/Smart City Coupe/Cabrio's exhaust

With the valve stuck in the wrong position, it can cause an excessive amount of soot or smoke to come from the exhaust 

Exhaust pressure valves play an important role in the operation of the EGR system and can affect engine performance and emissions when they have an issue. If you suspect that your MCC/Smart City Coupe/Cabrio's exhaust pressure valve may be having an issue, have the vehicle inspected by your local technician

In some cases it is possible to repair the exhaust pressure control valve, sometimes the valve gets stuck open/closed from the soot in the exhaust and it can just be a matter of cleaning the valve, in other cases, the valve will need replacing