kene

iTrader: (2)

I have (EDIT: temporarily)fixed my code 71: EGR. I did this by following ONLY the first step in the gs300 manual. And did the rest by my own methods.










I removed the cap to the modulator(very easily pops right off) and took out the small filter. It was somewhat stiff(felt like it could crumble) due to the "soot" from the exhaust gas that was passed through it.








I then went took some Purple Power degreaser(4.00$ at autozone, pep-boys, kragen, etc.) and gave the filter a good 4 sprays up close, and then pressed the degreaser out of it, I repeated this procedure 3-4 times until the degreaser that came out of it was its original purple color. I then ran the small filter through water to absorb water and squeezed the water out over and over again until I felt confident that there was no degreaser left in the filters fibers. The end result is a much brighter grayish colored filter that is now soft and not stiff anymore.








I also went even further and unplugged the 4 vacuum small lines(3 lines on top, and 1 on the bottom of the Vacuum Modulator) that are connected to the EGR Vacuum Modulator, and sprayed the purple power degreaser directly into the empty EGR Vacuum Modulator, and cleaned it out with a paper towel. I did this procedure 2x's. Just in case there was any gunk in there.






After ward I had put everything back together, and the light was still on. I forgot that I had to disconnect the battery for the ECU to reset the check engine code. So, I disconnected the battery, then put the key into the ignition and tried to start it up 2x's(this is to discharge whatever electricity is still in the system). I then went back and re-connected the battery. and started the 2jzge up and everything was fine. no more Check Engine Code 71 EGR Malfuntion.



I hope this helps others out.
kene

GS300 I6

iTrader: (2)

how long did you drove with a clean egr modulator? When i disconnect the battery, it usually comes back after 150-200 miles of highway driving.

kene

iTrader: (2)

I just did this mod today, I will keep an eye out for the light.

GS300 I6

iTrader: (2)

did the code come back?

kene

iTrader: (2)

Actually yes it did not too long ago. But with this mod(and also further spraying the vacuum modulator holes) I was still able to pass smog.(granted I reset the ecu as well so there was no Check engine light)

Funny thing was I did a pre-smog(30$ mock smog test) and my NOx at 25mph passed, but the 15mph was right on the max allowed limit line. So I went and further sprayed the modulator and blew the black gunk out carefully from the modulator's vacuum holes, and reset the ecu again just in case.

I then went back and had the car smogged again but at the test only place across the street, and now this time my 15mph NOx levels were good, but my 25mph NOx levels were right on the max allowed limit line. Either way I passed. And when I showed both business owners/technicians they were kinda stumped. So I don't know.
Great thing is I passed, and I didn't have to spend 200$ to do so.

Is300Tree2

I did the same thing before you posted this ( i was replacing valve cover gaskets) and it only stayed away for about a day or 2. Luckily I can get a new EGR for 70$ cus i used to work at lexus.

kene

iTrader: (2)

Yeah I want to get a new one too as well. I wonder if there has ever been a group buy on a EGR Valve? I know stuff like that happens in the private sector, but I always wondered if dealerships were cool like that?

oldkystude

I was working on the code 71 problem today on my son's 91 LS400. I read the check procedure in the manual for the EGR Vacuum Modulator (EVM). Probably a good check procedure but the EVM looked like a simple diapragm device, with the lower side subjected to exhaust gas pressure. I put a hand operated vac pump on the lower port in the center bottom. (It leads to the lower area of the egr valve). The pump could not pull a vacuum. Blowing in the same bottom port caused chunks of carbon to come out of the small top ports. Bingo! I then cut the stainless band off of the modulator and confirmed a 1/4 hole in the diaphragm. The upper section of the valve (where the 3 small P, R and Q ports lead) was full of carbon. The filter was dirty and the part of the element just above the small outer hole was black. There was also a lot of carbon under the filter. Now I'm going to make some rash statements of opinion that you guys can chew on:

1. If you see carbon in the filter cavity, or any of the small upper hoses, the diaphragm is leaking and you need a new EVM.
2. If your small upper EVM hoses are cracked from excess heat, the hot gasses are probably getting to them via a bad EVM Diaphragm.
3. If you can blow air thru (or not pull a vacuum with a pump) the lower large air port on the EVM, the diaphragm is shot.
4. If the filter shows any evidence of carbom on the side facing the valve, same problem.

If the diaphragm is intact there will be pressure applied to it when the EGR valve opens, but there will be no hot gas flow. This is key. A dead-headed line will get warm but once the diaphragm begins to leak even a little the problem will accelerate as the hot gasses begin to continually flow into the EVM, and back into the intake manifold thru the small sense lines on top of the EVM. It looks like these gasses will now begin to flow over the butterfly valve in the throttle body and could cause it to carbon up. It also looks like an open EGR valve will (intentionally) flow gasses only into the lower part of the intake manifold. The system is certainly designed to tolerate that flow, but the gasses were never intended to get upstream of the throttle butterfly valve as they may have in this car. I'm guessing that this 200,000 mile Lexus LS400 has a very nasty intake manifold, but that project will not be tackled this weekend. No way to get a new EVM Sunday, so Ill hit the local Pull-A-Part in the AM and hope I get lucky.