The engine exhaust emission light on

EGR (exhaust gas recirculation) valve helps to reduce the exhaust emission of automobiles. It recycles some gases discharged from the engine by returning them to the intake manifold, where the engine can burn these gases again, thus reducing emissions.
The exhaust gas recirculation valve is located in the engine compartment (under the hood). Most engines need exhaust gas recirculation to meet emission standards. If the exhaust gas recirculation valve is broken, the car will not pass the exhaust. My Suzuki Jimny has had such a question before, so I am more qualified to answer this question

EGR valve.

Only a few general concepts, keep in mind that the exhaust gas recirculation (EGR) valve is an integral part of a vehicles emissions control systems. It operates under the premise of lowering combustion chamber temperatures to reduce the amount of pollutants created by the combustion process. Being closely tied to the combustion process, this valve's operation has direct effect on the overall performance of the engine. Poor or faulty operation of the EGR valve can result in several notable symptoms and leads to increased pollutant emissions.

Poor Idle: An improperly closing EGR valve will act as a vacuum leak, disrupting the correct fuel and air mixture, causing a lean mixture condition. This results in misfiring cylinders and poor engine idle.

Overheating: The basic function of the EGR valve is to introduce exhaust gases into the combustion chamber at specific and controlled rates, lowering combustion temperatures, and lowering pollutant emissions. An EGR valve that does not open properly fails to introduce sufficient amounts of exhaust gases, causing combustion chamber temperatures to rise, leading to overheating of the engine.

Poor Fuel Economy: A sticking EGR valve will not open and close at the proper rate, leading to a reduction in the efficiency of the combustion process due to the lean fuel-air mixture it causes. This results in the engine having to work harder to perform the same amount of work, requiring more fuel to do it. On-board computer systems can also try to compensate for this lean condition by introducing additional fuel to the mixture, further increasing fuel consumption.

Increased Emissions: EGR valves are designed to lower the emission of pollutants from the combustion process. This is done by lowering the temperature of the combustion process through the introduction of exhaust gases into the fuel and air mixture. Lowered combustion temperatures result in more efficient burning of the fuel and air mixture, and less pollutants in the exhaust emissions. An improperly operating EGR valve will not correctly lower combustion temperatures, causing noxious emissions to increase, which can cause a vehicle to fail emissions inspection.

Test cylinders compression and check if some fault code is stored in the PCM 9computer).

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THE EMISSION SYSTEM IS DESIGNED TO TRAP AND STORE FUEL VAPORS THAT EVAPORATE FROM THE FUEL TANK.THROTTLE BODY AND INTAKE MANIFOLD DURING NON OPERATION OR IDLING STORE THEM IN THE CHARCOAL CANISTER AND THEN ROUTE THEM INTO THE COMBUSTION CHAMBER TO BE BURNED DURING ENGINE OPERATION.THE PCV VALVE ITS PART OF THE EMISSION SYSTEM.IT SCAVENGING CRANKCASE VAPORS IT DOES THIS BY CIRCULATING FRESH AIR FROM THE AIR CLEANER THROUGH THE CRANKCASE WHERE IT MIXES WITH BLOW BY GASES AND IS THEN REROUTED THROUGH A PCV VALVE TO THE INTAKE MANIFOLD.THE CATALYTIC CONVERTER IS PART OF THE EMISSION SYSTEM IT REDUCE POLLUTANTS FROM THE EXHAUST GAS STREAM IT LOWERS LEVELS OF OXIDES OF NITROGEN AS WELL AS HYDROCARBONS AND CARBON MONOXIDE.THE EGR VALVE PART OF EMISSION SYSTEM IT LOWER OXIDES OF NITROGEN EMISSION LEVELS CAUSED BY HIGH COMBUSTION TEMPERATURES.THE EGR VALVE RECIRCULATES A SMALL AMOUNT OF EXHAUST GASES INTO INTAKE MANIFOLD.SMOG PUMP IS ALSO EMISSION CONTROL COMPONENT IT INJECTING AIR INTO THE EXHAUST DOWNSTREAM FROM THE EXHAUST PORTS TO HELP COMPLETE THE COMBUSTION OF ANY UNBURNED GASES AFTER THEY LEAVE THE COMBUSTION CHAMBER.

Not necessary to replace any components, but the engine Exhaust Gas Recirculation (EGR) system needs to be cleaned inside together with the intake manifold, (both EGR throttled valve and intake manifold).

The EGR valve helps your car more efficiently and completely burn fuel by recirculating a portion of your exhaust and running it through the combustion process again. When the EGR valve goes bad, it must be replaced.

The EGR valve, or Exhaust Gas Recirculation valve, is a vacuum controlled valve which allows a specific amount of your exhaust back into the intake manifold. This exhaust mixes with the intake air and actually cools the combustion process. Cooler is always better inside your engine. The exhaust your EGR valve recirculates also prevents the formation of Nitrogen related gases. These are referred to as NOX emissions, and are a common cause for failing emissions testing. Unfortunately, your EGR valve can get stuck, causing NOX gases to build up. You'll know if your EGR valve is stuck or malfunctioning because your car will experience symptoms like rough idle and bucking on acceleration.

Here is a picture of where the EGR Valve is located (Accord 1999). Replacing it is fairly simple and straightforward. A vacuum line and a couple of bolts. You'll see what you have to do when you look at it.



If you are replacing the EGR Valve due to the Check Engine Light (MIL) being on with a DTC P0401 then I suggest contacting your Honda Dealer. There was a Product Update Campaign (PUD) in the fall of 1999 that corrected the problem.

Another times, the clean is the solution...I hope help yoiu with this. Good luck, and remember rated this help.

P0404 EGR valve problem
Change the Exhaust Gas Recirculation valve.
This valve puts some of the exhaust gas back into the engine to cool combustion (to reduce spark knock) and lowers HC (emissions).

PO 455- Evaporative emission control System leak detected (check exhaust system, egr valve, or entire intake and exhaust system)


PO440- Evaporative Emission System Malfunction (also check oxygen sensor)

The EGR valve helps your car more efficiently and completely burn fuel by recirculating a portion of your exhaust and running it through the combustion process again. This results in a cooler, more complete burn of the fuel which decreases you car's noxious emissions by prohibiting the formation of some harmful gases.

The EGR valve is vital to your car's emission controls.

When the EGR valve goes bad, it must be replaced - it cannot be repaired.

EGR Valve = Exhaust Gas Recirculation Valve.

The EGR valve controls formation of noxious emissions.

Rough idle and poor acceleration can be caused by a faulty EGR valve.

The EGR valve, or Exhaust Gas Recirculation valve, is a vacuum controlled valve which allows a specific amount of your exhaust back into the intake manifold. This exhaust mixes with the intake air and actually cools the combustion process. Cooler is always better inside your engine. The exhaust your EGR valve recirculates also prevents the formation of Nitrogen related gases. These are referred to as NOX emissions, and are a common cause for failing emissions testing. Unfortunately, your EGR valve can get stuck, causing NOX gases to build up. You'll know if your EGR valve is stuck or malfunctioning because your car will experience symptoms like rough idle and bucking on accelertaion.

The only short term problem is a decrease in gas mileage - but it should really be replaced before sensors become sooted or your cat. convertor gets overworked prematurely.

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this may be your egr valve, does it want to stall when its ticking over.