EGR and code 71 (1 Viewer)

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I am having a code 71 on my 94 LC, I have read about every thread I could find regarding this problem.

I checked:
1. Modulator & filter element, the modulator is the blue one so it has been replaced, it was total clean, no carbon what so ever, the filter was very clean, in fact it looked brand new.

2. All lines to the modulator, clean and free.

3. Tested EGR, passed
(First cut the problem domain in half by seeing if EGR is working when the valve is activated:
Disconnect the vacuum hose from the modulator to the EGR valve, this one will be pluged by your finger, then remove the second line of the tee fitting and put a long piece of hose on it(see picture), this is the one you will suck on. With the engine idling, suck on free end of the long hose. If the engine dies, then you know that the EGR valve is working and the passage is clear enough to flow exhaust gas)

I read on here if the you have a 93 or 94 and get a code 71 then it is your EGR temperature sensor. Where is the EGR temperature sensor and how do I clean it? I do not have the FSM from Toyota so if could please post a picture.
Picture.jpg
 
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I found this in another thread:

"EGR valve:
To test that your EGR valve is good, do the following: Plug the vacuum port on the right side of the EGR valve (stick you finger on it, whatever). Find the vacuum line that connects between the left side of the EGR valve and what looks like the intake chamber. It's really connected to a brass tube that runs through the chamber to the VSV that sits inside the curve of the chamber. Pull off the whole line and make sure it isn't clogged, then replace the end on the EGR valve, and with the engine idling, apply vacuum to it. The FSM shows some sort of vacuum pump. You could connect it to another vacuum line or port on the engine. I used my mouth, and just uh, well you get the idea... didn't taste too bad. The engine should falter/shudder/stall, indicating that the EGR valve is good. If not, there's probably something wrong with your EGR valve, try removing and cleaning/replacing it."

Just not sure which lines he is referring to.

***OK I updated the picture:
1. Red arrow is the one you unplug and plug with your finger.
2. Blue arrow and the one you unplug and attach a line long enough so that you can such on it.

I just did the test and my engine did stumble, could not make it stall but clearly my sucking was have an impact on the engine idle. So I should eliminate the EGR as being the problem.

Next up will be the EGR temperature sensor. Anyone know where this thing is? I spoke with Craig he has a 95 so his is in a different place then mine. Any know where this thing is on a 94?
Picture 003.jpg
 
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Well on the way into work this morning the check engine light turned off. I am calling C-Dan to order the FSM for my 94, so if it comes back on I will be able to locate the sensor. I will keep this thread updated if anything else happens.
 
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Jefferson
The light was on and off at first for me too, but now it has been on for the past two years straight and I just ordered a new EGR temp sensor, modulator, and VSV today. Good luck.
 
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Just checked this morning and I have the same code "71". Newps, thanks for the the info. Whew... I thought I was going to be the only person with this problem.

Any idea where the sensor is?
 
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:doh: While doing work at the shop two hose lines from the modulator were left disconnected. Problem fixed. Man. I wish they were all this simple.:grinpimp:
 
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Newps, the photos you showed were more of the EGR vac modulator not the EGRvalve. The EGR valve has the green sticker on it not the blue. The one with the blue sticker is the EGR vacume modulator. If you look right under the EGR valve the gas temp sensor will be right directly between the EGR vac modulator and the EGR valve just below the lip of the valve. Hard to describe but give it a try and have a look. Follow the EGR pipe to the EGR valve, call that the 12 oclock position and go to the 9 oclock position on the EGR valve and up an inch and its' right there. HTH
 
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TEXAS !!!
In my case, the 71 was thrown by the port that goes from the valve down across the top of the intake being plugged right where it opens into the top of the throttle body.

Double check that; it''s far cheaper than all those other parts. I replaced them all anyhow, but they were not the issue.

You could probably pull the black intake hose that attaches to the throttle body off, shine a light in there, open the throttle by hand and use an inspection mirror to look into the body and see if that port is plugged. Mine had tons of carbon in it. You could most likely use some picks to break it loose of check the opening.

Good luck,

R.
 
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Jefferson
Replaced the Temp Sensor and the Modulator this past weekend. Seems to have worked so far for me. About 200 miles and no code yet...
 
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Newps I have faith that the light will come back. Another thing you can try is cleaning the Throttle body--Takes a good hour. In the following order you can start replacing parts after cleaning the TB--#1 EGR modulator, #2 VSV, #3 EGR valve, #4 EGR temp sensor--my light is out for now but I haven't driven it very far since I replaced the VSV, and the EGR modulator with the 2nd blue version. According to this board only one guy has had a bad temp sensor.... thought I had it fixed a few times--this is the only thing that has driven me crazy on my Cruiser.;)
 
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Somewhere in the foothills...
Rogue,

Long time since I've seen you here. We missed you! :D

-B-
 
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This is better news than I was thinking, I got a CEL on the way to work, I checked at work...code 71, I just fixed a code 28, I will check to see if there was much carbon, I did also clean the TB this weekend and noticed alot of buildup in the small vacc. pipes that go to the EGR vacc. modulator.
I will keep you poosted.
I <3 ih8mud ;)
 
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Loveland, CO
13 years later... folks still having this issue... how challenging.
 
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13 years later... folks still having this issue... how challenging.
any luck finding the issue? The dreaded CELCode 71 just came on my 80. Did a quick inspection due to it being night already and noticed the EGV valve left side tee is rusted and cracked. Not sure if thats my problem
 
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After struggling with passing emissions every time, even after replacing the whole egr system, cats, o2 sensors, etc... i ran across a thread where a guy put a BB in the vacuum line indicated by the blue arrow above (the one that goes out the driver side of the modulator "T"... I had failed emissions 5 times in a row (after trying all kinds of dumb things) It passed with FLYING colors.... Had been failing on NOx.. went from 6.5-7.8 down to 1.3ish!

Just a related share...
 

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