I need to replace the EGR Valve according to the report from the check engine report but I cannot find it to ge the correct part number. Where would this be on the engine?

P0406 - Exhaust Gas Recirculation Sensor A Circuit High
An improper voltage signal is sent to ECM through the valve

Early Models : The EGR valve control the amount of exhaust gas routed to the intake manifold. Vacuum is applied to the EGR valve in response to the throttle opening. The vacuum control the movement of the taper valve connected to the vacuum diaphragm in the EGR valve.



Late Models : The EGR volume control valve uses a step motor to control the flow rate of EGR from exhaust manifold. This motor has four winding phases. It operates according to the output pulse signal of the ECM. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECM does not issue the pulse signal. A certain voltage signal is issued so that the valve remains at that particular opening.



Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Engine hesitation

Possible causes
- Harness or connectors (EGR volume control valve circuit is open or shorted.)
- EGR volume control solenoid valve
- EGR temperature sensor and circuit

Possible solution
- Repair EGR harness or connector
- Replaced EGR volume control solenoid valve
- Replaced EGR volume control valve


Hope helps (remember to rate and comment this answer).

P1491 = Exhaust Gas Recirculation (EGR) Valve insufficient lift.

P1456 = Evaporative emissions (EVAP) control system leakage (fuel tank system).

Check the EGR valve for a failed vacuum diaphragm. Check the fuel filler cap to make sure it is the correct factory style, has a good check valve and is on tight.

Check your main relay. It powers the fuel pump and the ignition system. They are a known problem, with a high failure rate, on the 90-93 accords. I do believe it's worth checking.

Here is a picture of where the EGR Valve is located. 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.

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Technical Description

Insufficient EGR Flow
What does that mean?

EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor EGR (DPFE). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0401 code means that OBD detected an insufficient amount of EGR.
Symptoms

You may notice drivability problems such as pinging (a.k.a. pre-ignition knock) when the engine is under load or the vehicle is at higher speeds. There may also be other symptoms.
Causes

A code P0401 most likely means one or more of the following has happened:

* The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
* There is a blockage in the EGR (tube), most likely carbon buildup
* The EGR valve is faulty
* The EGR valve may not be opening due to a lack of vaccuum

Possible Solutions

In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.

* Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
* Clean out the EGR valve and/or tubing to remove deposits
* Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
* Replace the DPFE sensor (with a good quality / OEM one)
* Replace the EGR valve

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P0401: Isufficient Flow Detected in EGR system.
-clean the EGR port with the carburetor cleaner.
-clean the EGR passage inside the EGR valve with the caburetor cleaner.
Reset the light, if the light still coming back, then replace the EGR valve.

Perform a valve clearance inspection and adjust if necessary. Tight or sticking valves will cause a misfire or rough running concern. Note: Perform valve adjustment when the engine is stone cold. 4cyl: INT 0.26mm EXH: 0.30mm (V6 engine are hydraulic and no adjust necessary.) Also check for a sticking or stuck open EGR valve. For diagnostic purposes only: Remove the EGR valve. Place a business card over the EGR passage and bolt the EGR valve back on. This plugs the EGR ports and if the misfire goes away the EGR valve is partially stuck open and is defective.
Check for low fuel pressure. Check for low compression. Check cam timing. Check for a weak ignition coil. Also don't over look the possibility of worn or broken engine mounts which cause excessive engine movement and engine vibration. -hope this helps

there is no code that says replace these sensors,all codes say they is a problem in that sensor's circuit or flow with the egr valve,do you remember what the code number was before or what is it now?

Hi,

HOW TO INSPECT EGR VALVE

Before attempting to troubleshoot or repair a suspected exhaust gas recirculation (EGR) system on a vehicle, the following conditions should be checked and be within specifications.

• Engine is mechanically sound.
• Injection system is operating properly.
• Mechanical-vacuum advance is properly adjusted or the electronic advance system is operating properly.

If one or more of these conditions is faulty or operating incorrectly, perform the necessary tests and services to correct the problem before servicing the EGR system.




Before attempting any tests of the EGR system, visually inspect the condition of all vacuum hoses for kinks, bends, cracks, and flexibility. Replace defective hoses as required. Check vacuum hose routing. (See the underhood decal or the manufacturer's service manual for correct routing.) Correct any misrouted hoses. If the emissions system if fitted with an exhaust-gas-recirculation valve position (EVP) sensor, the wires routed to it should also be checked.
If the EGR valve remains open at idle and low engine speed, the idle operation is rough and surging occurs at low speeds. When this problem is present, the engine may hesitate on low-speed acceleration or stall after deceleration or after a cold start. If the EGR valve does not open, engine detonation occurs. When a defect occurs in the EGR system, a diagnostic trouble code (DTC) is usually set in the powertrain control module (PCM) memory.

Cont....

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.