[landtoy80]

EGR FA?
71, P0401, P0402 Codes from the ECU

Your check engine light is on and you have one of the Codes stored in you ECU.

The EGR is a common problem with the FZJ80. The EGR system lets some exhaust gas, from the exhaust manifold, cycle back into the intake chamber to reduce emissions. This is good for the environment but not good for your motor.
From what I have learned is that the modulator is the big problem. It is a diaphragm that is opened and closed via exhaust gas. It brakes down over time and lets carbon get into the vacuum system. Toyota must of learned that the FZJ80 modulator was faulty as in later years they replaced the modulator with one that was used on the FJ60. If you have the modulator with the green top, replace it with a new one, the blue topped one. Checking several times a year would be a good idea.

These are some tip to get the EGR system working again.

EGR=Exhaust Gas Recirculation
Code 71=EGR System Malfunction
P0401=Exhaust Gas Recirculation Flow Insufficient Detected
P0402=Exhaust Gas Recirculation Flow Excessive Detected.
FSM= Factory Service Manual
ECU= the computer
Red arrow is the modulator.
Green is EGR



After every test, reset the ECU by removing the EFI fuse (in engine bay) for a
several minutes.

1) First check the modulator to see if carbon is in it. If so replace the modulator.
If there was a lot of carbon in there you might need to replace or clean the vacuum hoses.
Take the cap and filter out of the modulator, note how the filter is in there as it needs to go back that way.
If your modulator looks like Darwood’s (below pic) then you indeed need to replace it and clean or replace any contaminated vacuum hoses.

Test the modulator per the FSM

2) If your year has a temperature sensor remove it and clean the tip.

3) Test the VSV per the FSM. The VSV is an electromagnet that opens and closes the vacuum in the vacuum system. If a chunk of carbon gets in the diaphragm it will make the VSV fail. It could if failed once, causing the CE light to come on but then the carbon could of gotten sucked out of it and test ok.
To remove it for the first time it is best to remove the intake chamber as it is tight under there and the screws are tight. Do this when you clean the intake chamber.

4) Test the EGR per the FSM. If your light has been on for a long time carbon could buildup so that the EGR can’t open and close.

5) Clean the intake chamber. The port inside the intake chamber gets plugged with carbon to the point that it is almost plugged. You need to remove the intake chamber to clean it. It cleans up fine with carb. cleaner. Clean the throttle body while you have it off too.



Added Comments from Semlin

1. if you have a 93 not from california you will have no EGR temp sensor which means your EGR system may not throw a code 71/check engine light even if it is not functioning.

2. If you need to remove the EGR valve, the union EGR pipe bolt is a doozy. It is about a 32 or 34 mm bolt and hard to access to get a turn on it. A big wrench may not fit. Robogrips or similar is best. There is also a wire loom right beside the pipe that restricts access where you need it and has been known to break down from heat in the area (mine has some asbestos cladding) You need to be careful not to mangle this loom with the wrench you use as the wires inside may be brittle.

3. you can remove the VSV for EGR without removing the air intake chamber. I just did this two weeks ago, and if I can do it anyone can. You need a 30" extension bar for a 12mm socket to undo one of the screws that holds the vsv assembly on (clearly visible from underneath once you look for it), and then you need either an open 12mm spanner or maybe a box wrench for the other bolt accessed from the ds side under the intake chamber (finicky). The bolts were stiff and had never been removed before on mine but they broke away ok. I found it much easier to remove the whole VSV bracket assembly from the throttle body side of the air intake chamber after removing all the vacuum hoses and switches (and also after removing the throttle body - see next comment). At that point it was easy to remove the bolt holding the vsv to the bracket with an impact screw driver.

4. if your system has not been serviced for a while check every vacuum hose and also the metal tubes too (e.g., the ones on the VSV bracket, and originating from the throttle body). You particularly want to check the hose that runs from the EGR, through the intake chamber and then to the vsv. Blowing through one end will tell you if it is blocked where is passes through the intake chamber.

[Roget]

Hey, I have been following this thread about the dreaded P401 and was able to narrow it down to the VSV valve. I took your advise and was able to remove and install the new one in short time!!! The P401 has gone away!!!

Again thanks
Roget

[FJason80]

Could someone please add pics to this FAQ?

[roncruiser]

This is very informative. Pics would be very helpful.

[gibbs1979]

How imperative is it to get this fixed? I'm not too concerned about emissions at the time.

[Cj80cruiser]

Originally Posted by gibbs1979

How imperative is it to get this fixed? I'm not too concerned about emissions at the time.

I've had problems with my EGR system since the day I bought it. I've done nothing to fix it. Sometimes I'll have low RPMs at idle which is a pain but I just deal with it.

[tltaylor22]

I had an EGR code on my 97 for almost a year after I bought it two years ago. The dealer threw $1300 in parts at the problem on thier dime and gave up trying to fix it. I spent less than an hour under the hood and had it fixed. #4- clean the metal tube that runs through the intake manifold between the EGR and the VSV. Be careful not to punch a hole in the rubber tube on the bottom of the manifold. This fixed mine.

[Cj80cruiser]

Originally Posted by tltaylor22

I had an EGR code on my 97 for almost a year after I bought it two years ago. The dealer threw $1300 in parts at the problem on thier dime and gave up trying to fix it. I spent less than an hour under the hood and had it fixed. #4- clean the metal tube that runs through the intake manifold between the EGR and the VSV. Be careful not to punch a hole in the rubber tube on the bottom of the manifold. This fixed mine.

What's your trick? I mean I could care less about cleaning the tube but how'd you get $1300 of free parts from the dealership?

[beno]

Sawzall and a backing plate took care of all of my EGR issues.

Life couldn't be better.

[Cj80cruiser]

Originally Posted by beno

Sawzall and a backing plate took care of all of my EGR issues.

Life couldn't be better.

This sounds more my speed. Beno is there a thread on what I would need to do to rid myself of my EGR system assuming that's what you mean by sawzall and backing plate?

[Beowulf]

Originally Posted by roncruiser

This is very informative. Pics would be very helpful.

It was a 5 year old thread and there were many, many images lost during the 2 or 3 software upgrades that Woody has done over the years. You might PM Kirt and see if he still has those pictures. Otherwise, you are out of luck.

-B-

[roncruiser]

Originally Posted by Beowulf

It was a 5 year old thread and there were many, many images lost during the 2 or 3 software upgrades that Woody has done over the years. You might PM Kirt and see if he still has those pictures. Otherwise, you are out of luck.

-B-

Way ahead of you... Kurt already said he'd send me the pics. I'll repost the pics when I get them.

[tblume]

[beno]

Originally Posted by Cj80cruiser

This sounds more my speed. Beno is there a thread on what I would need to do to rid myself of my EGR system assuming that's what you mean by sawzall and backing plate?

There isn't much to this.

I used a sawzall for the EGR because the big nut hooking the EGR valve to the downpipe to the back of the head was rusted beyond belief, and since I wasn't going to replace the system, the sawzall was a good idea.

Basically, what you need to do, is take the EGR gasket that goes to the throttle body, create a template of it (or use it as a template), cut the metal, drill out the holes for the studs and put that in place of the EGR valve.

Now for the pipe going to the back of the head, that was a bit tougher. I had the head off, so things were really easy. Again, I used the gasket as a template and made another backing plate, drilled the stud holes out and put it on.

No issues whatsoever beyond blowing a P0401. Expected since I no longer have an EGR system.

DISCLAIMER: Do realize you are messing with the emissions system which is a big "no-no" in most state jurisdictions. Please do be aware of your local laws before you go doing this stuff because going back to an EGR system will cost a significant amount of coin.

Here are some pics.

[Cj80cruiser]

Does it run better without the EGR system vs. having a fully functioning EGR system?

[Cj80cruiser]

What happened to the EGR modulator and the vacuum hoses?

[beno]

Originally Posted by Cj80cruiser

Does it run better without the EGR system vs. having a fully functioning EGR system?

I have not noticed any change from before with the EGR system to afterwards.

Originally Posted by Cj80cruiser

What happened to the EGR modulator and the vacuum hoses?

Gone as are the vacuum hoses. The entire intake manifold vacuum lines (except for the fuel regulation ones) go back onto each other--almost a completely closed system.

-o-

[Cj80cruiser]

What about the EGR gas temp sensor...leave it unplugged? What did you cap the EGR pipe with?

You have any pics of the top engine showing what's missing and what's still there?

[beno]

Originally Posted by Cj80cruiser

What about the EGR gas temp sensor...leave it unplugged? What did you cap the EGR pipe with?

You have any pics of the top engine showing what's missing and what's still there?

EGR temp sensor is still plugged in. No reason to really disconnect it.

EGR pipe is gone. If you look at the 3rd picture above, that is the back of the head at the firewall. The pipe entered through this spot. It is now shut off with a backing plate.

Non-NA 1FZ engines have heads that have this casting as well. From my understanding, Toyota put a backing plate here as well, sort of like I did, because most non-NA 1FZ's do not have emission requirements in their operating nations.

I will try to get some better pics from above when I get home from work.

[Cj80cruiser]

I do have my FSM on disc and tried to post a pic but couldn't get the bugs worked out. Beno a few more pics would help tremendously. I will definitely be doing this once I figure everything out.

[Cj80cruiser]

Beno can you show me using this?

[beno]

Sorry for the delay...I'm terribly busy on my end.

Hope these pics are clear.

[nicholas]

Please excuse my ignorance, but does having a constant P402 or P401 due to having removed the EGR system do anything to the engines fuel efficiency?

I know that when I had a code for a bad O2 sensor I got terrible fuel mileage. Does the EGR system relay any info to the computer that effects air/fuel ratio like the O2 sensor system?

If not, I can see myself removing my EGR system if I ever get the dreaded code in a couple of years after I move back to Northern Idaho, the land of no emission laws.

[Cj80cruiser]

Originally Posted by nicholas

Please excuse my ignorance, but does having a constant P402 or P401 due to having removed the EGR system do anything to the engines fuel efficiency?

I know that when I had a code for a bad O2 sensor I got terrible fuel mileage. Does the EGR system relay any info to the computer that effects air/fuel ratio like the O2 sensor system?

If not, I can see myself removing my EGR system if I ever get the dreaded code in a couple of years after I move back to Northern Idaho, the land of no emission laws.

Excellent question....maybe someone will chime in for this.

[beno]

None that I am aware of. I have had it this way for almost a year now.

Many mini-truck guys have taken EGR valves off for a long time with no ill effects.

Read Robbie Antonson's answer to a question regarding EGR valves from the last TT issue. He makes pretty clear what the EGR valve does.

You can easily dupe the computer into thinking the EGR valve is still there by putting a resistor with the correct current into the EGR temp. sensor position and "tell" the computer the correct electrical value. The FSM has a test for this and basically you would mimic that test to show a positive value with the correct current running from the sensor to the ECU.

By getting rid of the EGR valve you are getting rid of almost 1000 degrees of heat at the back of the block. I don't mind that one bit.

-o-

[Cj80cruiser]

Thanks beno...my egr will be making a quick exit now.

[nicholas]

Originally Posted by beno

None that I am aware of. I have had it this way for almost a year now.

Many mini-truck guys have taken EGR valves off for a long time with no ill effects.

Read Robbie Antonson's answer to a question regarding EGR valves from the last TT issue. He makes pretty clear what the EGR valve does.

You can easily dupe the computer into thinking the EGR valve is still there by putting a resistor with the correct current into the EGR temp. sensor position and "tell" the computer the correct electrical value. The FSM has a test for this and basically you would mimic that test to show a positive value with the correct current running from the sensor to the ECU.

By getting rid of the EGR valve you are getting rid of almost 1000 degrees of heat at the back of the block. I don't mind that one bit.

-o-

That sounds great, I wouldn't mind losing that heat either. Perhaps that might have something to do with the HG warpage around cyl #6 that so many people have found.

Have you tricked your computer yet?

This makes me want to get my truck registered at my 's parents address just outside Coeur d' Alene, ID ASAP. I'd rip that system off in a heart beat even though I have not had any problems with it so far. (Knock on fake plastic LX wood trim)

So do you guys not have emission regulations down there in NM?

Just curious, but any idea if this mod is Shamen approved?

[beno]

Originally Posted by Cj80cruiser

Thanks beno...my egr will be making a quick exit now.

Again, please realize that this is illegal in some jurisdictions.

I will not be held accountable for anyone else's actions. I'm merely showing what I did, nothing more, nothing less.

Thanks.
-onur

[arndog123]

My LX started throwing the 401 code a couple weeks back every 20-25 miles or so. Clearing the code was starting to irritate me so I took the plunge today and started checking all the EGR components. The EGR valve, modulator, temp sensor and all hoses were fine. The port behind the throttle body where the exhaust gases flow was completely plugged w/ black soot. Cleaned it up, slapped everything back together including a new gas pedal cable and went on a 30 mile test drive. Woo hoo, no more check engine light.

I'd like to eventually get rid of the system like above on both Cruisers some time down the road. For now I'm just happy I don't have to keep clearing the code. I got rid of the EGR system on my '86 and haven't had any probs yet.

[Beowulf]

Originally Posted by beno

Again, please realize that this is illegal in some jurisdictions.

Actually, Beno is incorrect. Tampering with the emissions system is illegal in ALL jurisdictions in the USA.


http://autos.yahoo.com/maintain/repa...ques081_0.html

http://www.epa.gov/compliance/resour...mperpenpol.pdf

Revisions to the Clean Air Act in 1990 further broadened the definition of emissions tampering to include virtually ANY type of engine or exhaust system modification that alters what comes out the tailpipe. That means any nonstock aftermarket part that is installed on your engine must be EPA-approved and emissions legal.

Before the law was revised in 1990, it was only illegal for professional mechanics to remove or disconnect emission control devices. There was nothing to prevent a motorist from tampering with their own vehicles. That loophole has since been plugged.

Originally Posted by nicholas

So do you guys not have emission regulations down there in NM?

Yes, we have emission regs in NM. Beno lives in a county that does not test for emissions... yet. In my county, they test me randomly and they test every newly registered vehicle. The employees that work on some federal property are required to have emissions testing if they bring the vehicle on government property.

Is it illegal? Yes. The fine can be as high as $2,500. Will you be caught? Probably not. Would you be fined if you were caught? Probably not. The EPA has bigger fish to fry but that does not make tampering with the emissions system legal in the US.

-B-