What does an EGR fault code mean for a car?
An EGR-related fault code does NOT mean the vehicle is polluting. It might be producing elevated levels of NOX in the exhaust if the EGR system is not operating correctly. The only way to know for sure is to check NOX emissions with an exhaust analyzer.
How does a linear EGR valve work in a PCM?
“Linear” EGR valves use a motor to open the valve. The further the valve opens, the greater the flow rate. Linear EGR valves may also be equipped with an EGR valve position sensor (EVP) to keep the PCM informed about what the EGR valve is doing.
What should I do if my EGR is not working?
Common EGR problems include: Pinging (spark knock or detonation) because the EGR system is not working, the exhaust port is plugged up with carbon, or the EGR valve has been disabled. The fix here is to inspect the EGR system, remove the EGR valve and check the valve and port for carbon, and remove the carbon from the port if it is plugged.
What should my EGR reading be for a vacuum leak?
A normal reading is typically 17 to 22 inches Hg. IF the reading is low, it indicates a vacuum leak. Check all vacuum hose connections for loose or disconnected hoses. Replace any hoses that are cracked. If there are no obvious vacuum leaks, remove and inspect the EGR valve.
An EGR-related fault code does NOT mean the vehicle is polluting. It might be producing elevated levels of NOX in the exhaust if the EGR system is not operating correctly. The only way to know for sure is to check NOX emissions with an exhaust analyzer.
Why is EGR important to the p0401 code?
Usually on an OBD2 system that sets the P0401, the ECM/PCM must see the failure on two consecutive trips before it will permanently set the code and trigger the Check Engine Light. The EGR system is important because it reduces emissions by allowing burnt exhaust gas to flow back into the engine.
“Linear” EGR valves use a motor to open the valve. The further the valve opens, the greater the flow rate. Linear EGR valves may also be equipped with an EGR valve position sensor (EVP) to keep the PCM informed about what the EGR valve is doing.
Common EGR problems include: Pinging (spark knock or detonation) because the EGR system is not working, the exhaust port is plugged up with carbon, or the EGR valve has been disabled. The fix here is to inspect the EGR system, remove the EGR valve and check the valve and port for carbon, and remove the carbon from the port if it is plugged.