Greetings i own a Lexus ES300 1994 V6. My CEL is On the reading from Auto zone tool say EGR valve excessive flow and O2 sensor 1 bank 1. the car drives very smooth with no issues/hesitation
1-i replaced the Valve still get the same cod. ((EGR valve excessive flow)) i checked the hoses by spraying carb cleaner no change in the idle speed no noticeable air leak
2-replaced O2 sensor the rear one the cod is cleared for O2 sensor.
3-Cleaned the throttle body and the AFS, Idles at 600 rpm with slight movement up and down noticed on the rpm needle
4-i noticed an exhausts leak in the exhaust pipe before the CAT converter.
5-Bad fuel economy, i can tell that it is burning a lot of fuel very fast, the exhausts smells different than it used to be

 

If you have an exhaust leak upstream of the cat converter, of course you will get different exhaust smell. And it will throw off your O2 reading which will contribute to your bad fuel economy.

Fix that exhaust leak!

 

Thank you for your advice i went to a mufflers shop and for my surprise there was no Cat converter in my car the previous owner decided to remove it and weld a straight pipe.so i installed one of the universal Cat converters no more exhaust leak.
i did not reset the CEL yet, I've been driving it for a day the light still ON,but the smell from the exhaust is completely deferent.do you have any advice for at this point? i would appreciate your help.I will post any updates

 

To clear the CEL, remove the EFI fuse for 30 seconds.

 

Thank you.i did clear the CEL code i have been driving it without the light for few days and now its back ON.Auto Zone scan tool reads the same EGR OVERFLOW; is there anything that i am missing here, just an idea or a hint of what else it could be i feel like i am the only one who get this type of Code reading.

 

What is the exact code number?

 

P0402
This what the scan tool been reading for months

 

Your most likely culprit is the sensor that measures EGR flow - the DPFE sensor... it looks for a pressure differential and tells the computer how much differential it sees... There is a test for this, but you would need the service manual or a subscription to Mitchell or perhaps Alldata for the specifics, as I don't remember - something about checking voltages with EGR open and closed...

The only other possibility I recall seeing with the EGR related codes, and most likely not in your situation, but, the only other thing that usually happens is that the passages get blocked... essentially, wherever the EGR valve mounts, the passages in and behind that can get blocked with the emissions soot and cause EGR faults... Usually not in an excessive flow condition, but, its always worth a shot. To clean, you will need brake cleaner (a couple cans, depending on how much is built up), and something wiry and thin to stick in the hole to ream it out... It might be best to have a diagram of where the EGR goes on some vehicles. Obviously, you already know where the valve is, but, where the passages go... The outlet for the EGR is inside the intake manifold and sometimes, depending on amount of soot built up, it may need removed and taken to a machine shop or the likes that can clean it in an acid wash solution...

If it were me, I would try and clean the passages first (this is only a good thing, regardless), and then the DPFE sensor...

 

Thank you for your advice i already done the passage clean up procedure and it was not clogged at all; actually i did not get any thing out of it.I don't have the car manual because apparently there is no specific book for this model and the Toyota Camry engine manual has a different EGR type, I have tried to locate the MAP sensor but with no luck so far i might to look harder or you can help me locate it.

 

not MAP sensor, DPFE sensor...

I don't recall where it is located though, sorry...

 

The light went off for 3 days then;came back ON and stayed. the scan tool reads the same error code,apparently there is no solution for my situation. i just feel that the problem is in the vacuum control on the other end of the the main vacuum tube on top of the EGR; is there a way to test if it is applying enough vacuum to move the EGR valve?

 

go back and re-read my post... your problem is most likely the DPFE sensor...

 

Thank you, i did read your post and conduct an on-line search for the location of the DPFE sensor in my V6 Toyota engine but apparently the company did not use this type of sensors in this specific model unlike Ford who used it in almost every engine.

 

You would need to check out the EGR's VSV. That's the valve that provides vacuum to the EGR to make it operate.

Toyota doesn't use DPFE on their EGR system.

 

sorry, its not called DPFE then, is the vapor pressure sensor... its two different names for what ends up being the same thing - its the thing that measures egr flow... one is a pressure sensor, the other is differential pressure sensor...