The EGR valve is the heart of the EGR system, and therefore care must be taken if it fails. Like any other auto part, the EGR valve can end up failing. When that happens, you may notice that your vehicle exhibits one or more undesirable symptoms. Stay and discover here the common failures of the EGR Valve .
Nitrogen oxides (NOx) from a car’s exhaust can contribute to the formation of photochemical smog pollution. All modern gasoline-powered vehicles (and most diesel applications) combat the problem by limiting NOx emissions with an exhaust gas recirculation (EGR) system.
What is the EGR valve?
As mentioned, the EGR system reduces the amount of NOx emissions coming out of the vehicle’s tailpipe. The system does this by recirculating spent exhaust gases back into the engine to reduce combustion temperatures.
By substituting a portion of the engine’s normal air-fuel mixture with inert exhaust gas, the combustion temperature is lowered, which also limits the formation of NOx.
But exhaust gases can only enter the engine under certain conditions. If EGR takes place at the wrong time, the vehicle will suffer from engine performance problems. For this reason, the EGR system contains an EGR valve to regulate the flow of exhaust gases.
Normally, the EGR valve is located in the intake manifold of the engine. A tube connects the valve to the exhaust manifold . When the conditions are right, the EGR valve opens, allowing exhaust gases to enter the engine, where they are burned as part of the normal combustion process.
There are many different designs of EGR systems in use today. On some older vehicles, the EGR valve is directly actuated by engine vacuum and exhaust gas back pressure. Most modern vehicles, however, use one or more electronically controlled solenoids. Solenoids can control the supply of vacuum to the EGR valve or actuate the valve directly.
A computer, often referred to as a powertrain control module (PCM) , actuates the solenoids based on information from various sensors.
Common EGR Valve Failures
When the EGR valve goes bad, it can cause several noticeable symptoms or signs. Here are the most common EGR Valve failures.
1- Engine light illuminates
The PCM controls the operation of the EGR system. If the module detects a problem, it will turn on the check engine light and store a corresponding Diagnostic Trouble Code (DTC) in memory.
2- Engine performance problems
When the EGR valve goes bad, it can cause various engine performance problems, including rough idling, stalling, overloading, and hesitation.
3- Spark blow (detonation)
A stuck EGR valve can lead to abnormally high combustion temperatures, resulting in spark knock (also known as knocking). If left unchecked, spark kick can cause expensive engine damage.
4- Starting problems
Although rare, if the EGR valve is stuck open, it can make it difficult to start the vehicle.
5- Increased tailpipe emissions
When the EGR valve fails, it can cause an increase in nitrogen oxides (NOx), hydrocarbons (HC), or both. If you live in a place that requires emissions testing, an increase in these pollutants will cause your car to fail the test.
How to test the EGR valve?
Several common EGR Valve failures can tell you that an EGR valve is broken or damaged. To make sure the valve is the culprit, you’ll want to run a full diagnostic on the vehicle by doing the following:
1. Check Diagnostic Trouble Codes (DTCs)
The first thing to do is check for DTCs that may limit the troubleshooting process. Cars made after 1996 with On-Board Diagnostics (OBD) II often set a code when there is a problem with the EGR system , as do some older cars with OBD I.
You can check diagnostic trouble codes using a scan tool or code reader. Nowadays, you can even get a cheap OBD II code reader for your smartphone.
It is important to note that DTCs do not tell you the exact problem with the car. The codes simply serve as a starting point for further diagnosis.
2. Perform a visual inspection
Next, you will need to perform a visual inspection. Look for problems such as broken wires and damaged vacuum hoses in the EGR valve control system. Repair the problems found during the visual inspection, clear the DTCs, and see if the problem reappears.
3. Test the EGR valve
Because there are so many EGR system designs in use today, there is no one-size-fits-all test method for the EGR valve. To correctly solve the EGR system of your vehicle, you should know these problems that we are presenting to you about the common failures of the EGR Valve.
How much does an EGR valve cost?
Expect to pay between $350 and $1000 to have a professional replace the EGR valve for you. If you do the work yourself, expect to pay between $20 and $800 for the part. The exact price of the repair will depend on several factors , such as the year, make and model of your vehicle.