Recently we had a customer call on the phone requesting a quote to put an EGR Valve on his car. When someone calls our shop with a specific quote request like that, my first question is always, “why do you think it needs an EGR Valve?” He said what many customers say, “My Check Engine Light is on and I got a diagnostic from the local Retail Auto Parts Store and they said that is what I need.” We all see the ads on TV that all you do to fix a car is plug a code reader into the car, read the code, look up the code on the internet, and replace the part that goes with that code! Unfortunately for a lot of consumers, it just isn’t that easy.
In this case the car had a P0401 insufficient flow code which means that the problem is in the EGR system not necessarily the EGR Valve, yes it could need an EGR Valve but it’s no guarantee that a new valve will fix it. Please understand, it could be the vacuum lines have a leak, the EGR Valve Solenoid may not be getting the electrical current, OR the ports to the EGR Valve could be clogged? Basically, the code gives us hints where to start looking for the problem by telling us what symptoms the car has. There are a lot more steps to the proper diagnosis of your engine troubles than just plugging in the code reader and replacing parts.
We have seen over and over where a customer has gotten the parts store diagnostic and after spending hundreds of dollars on parts alone, finally bring the vehicle to us to figure out what is really needed to fix the vehicle and keep that Check Engine Light off! If you are just swapping parts, you are shooting at a moving target with a blind fold on! Sure, it sounds convenient and easy to have someone diagnose your car in the parking lot of the Parts Store for free, but it isn’t necessarily going to fix the real problem that your engine is experiencing. Skilled Technicians not only know how to use a code reader, but they also have gone through specific diagnostic training to know how to pinpoint the real problem without just switching all the parts until they get the right one. Don’t be afraid to call our shop and ask us to just take a look at your vehicle to diagnose the real problem. Diagnostic fees may seem like an extra charge, but if it prevents replacing the wrong part(s), it is totally worth it. Having your car diagnosed in the parking lot of the Auto Parts Store is a lot like asking the cashier at your local pharmacy to look at your rash and recommend the correct remedy when you really should be going to the Doctor.
Technical Stuff: EGR stands for Exhaust Gas Recirculation, what they are doing is recirculating exhaust gas back through the engine for emission control purposes. Because we are recirculating air with a high carbon content the passages to the valve can and do what we call carbon up, see attached picture. In this case we needed to take the passages apart and clean them out and on some vehicles this can take hours to get to all the ports.