'97 FZJ80 Check Engine Light (MIL)?

[Chuck_FJ60]

My wife's truck's check engine light has come on and off intermittently for the last few weeks. I asked my shop to check the code and it's showing #0401. Can someone please check what this is?

Thanks in advance for the help.


Chuck

 

[Chuck_FJ60]

OK, I searched several ways and finally found some answers to Code #0401. I'll read up on the FAQ.

Chuck

 

[Rogue]

EGR...

 

[Beowulf]

Chuck,
There's more information about the P0401 on this site than is in the FAQ. A *lot* more.
-B-

 

[Chuck_FJ60]

Thanks so much Rogue & Beo for the replies. I checked the modulator, and it's clean as a whistle... Are there scanned pages regarding the EGR testing somewhere in this site. Can someone please tell me the steps for testing if you have the time? I don 't own an FSM yet :-(

Thanks,


Chuck

 

[Beowulf]

Chuck,
Have you looked for the P0401 and the EGR testing here on IH8MUD? There really is a lot of information on this subject.

You will need the FSM if you are going to do your own maintenance; particularly if you're pulling codes and trying to resolve emissions faults.

What is a JZA80 ?
-B-

 

[landtank]

A few weeks ago I threatened another forum member to stop by and look at his on going EGR battle since I was in the area. I took some time and reviewed the manual before leaving that week. I found a problem with the FSM in the trouble shooting area of the Modulator. AT one point they want you to run the engine at 2500 rpms and check for a certain condition of how air flows through the Modulator. If the Modulator fails the test then replace the modulator. They are wrong as it doesn't mean the Modulator is bad. It only means it's not functioning properly.

An easy check for a clogged tube or head passage would be to remove the tube to the bottom of the Modulator and check the pressure at 2500 rpms. I'll try this later and report my readings. I recently had my head off and all the passages where wide open.

Got some unexpected results. At idle the guage fluctuates between 0 and 3 in. hg Vacuum. Then as you rev the engine it slowly drops at a steady 0. Hooked it up to both my vehicles with the same results.

 

[Chuck_FJ60]

Beo,

Yes I read through the EGR FAQ Section several times. I just wondered what the various methods of testing were that were listed in the FSM. I have the Haynes SM at this time, but realize I need to order my FSM, just hadn't had time. I also wanted to try tackle these EGR issues this Sunday when I have some spare time. I will remove the modulator & EGR to check if there's any blockage.

Again, thanks!


Chuck

 

[semlin]

Chuck, if your modulator filter is totally clean then you don't have the typical 401 fault which starts at the modulator. You can confirm this by checking the vacuum hoses around the modulator to check for deterioration, blockage and rust from exhaust leaking into the lines.

You can pull the throttle body and EGR valve to check the EGR tube back to the intake plenum for carbon buildup and blockage. Be careful of the gaskets if you don't buy replacements.

You can clean the throttle body at the same time while you have it out and check that none of the EGR ports on top of the throttle body are blocked (blow compressed air through them and make sure there is unobstructed flow)

the fsm test is a little hard to follow and hence hard to set out for you here plus I can't remember. I am pretty sure beowulf is right that there are a lot of historic threads on this.

 

[Beowulf]

Chuck,

If you're serious about fixing the P0401 this weekend then you should be prepared to do some searching. I repeat....

There's more information about the P0401 on this site than is in the FAQ. A *lot* more.

-B-

 

[phatairman]

I currently have the wonderful P0401 code myself. Since I am a 1.5 mechanic. And I am trying to follow the FSM myself, while learning alot. But my question is will P0401 code hurt the engine? I have already pulled the modulator and it is clean. I wanted to check before driving alot with this problem.

Flaying in Atlanta,

Matt

 

[Beowulf]

Matt,
I struggled with a P0401 off and on for about a year. According to Toyota manuals, an EGR system that is not functioning properly can cause detonation. Your 80 has a knock sensor that will retard the timing but, in my case, I didn't hear any pinging or feel any performance changes with retarded timing. In fact, I couldn't tell any difference at all... it's just that darn MIL light staring at you every time you start the truck. Drove me crazy and I couldn't take the worrying that it might mask another problem.

There are 4 major components to the EGR system; the EGR modulator, the EGR valve, the EGR temp sensor, and the VSV for EGR. The failure can be in any of those and we have had people resolve their issues with each part. Sometimes a new modulator fixes the problems, sometimes a cleaing of the EGR valve and/or the temp sensor. Several have found a defective VSV and replacing it fixed the problem.

In addition to the 4 components, there are various hoses and electrical connections. Some have found hoses connected incorrectly; some have found clogged hoses; some have found hoses disconnected. Dan reported that a Toyota Master Mechanic struggled with a customer's EGR problem and evenually found a clogged passageway inside the manifold. Hoses are the cheap fix if you're lucky.

A few have found that clearing the P0401 was all that was needed and the code has not returned. That's a real cheap fix.

Bottom line is the EGR system a SYSTEM. There isn't a silver bullet fix. As Rick (landtank) has explained to many people with this problem, you have to approach it with knowledge, reference material, testing tools, and then tackle the problem systematically. Or you can take my approach and buy and replace individual pieces until you deplete the Cruiser fund then take it to someone you trust and pay them to fix the P0401.

-B-

 

[snowcruiser]

Someone (mechanic) you trust? Must be nice to live in that part of the country. This doesn't exist near Pennsylvania that I am aware of. Anyone beg to differ?

 

[Chuck_FJ60]

Now I'm ready for some closure to our P0401 problems...

I finally got around to change the VSV for EGR. Purchased it locally for $ 76 plus tax from Champion Toyota.

I tried so hard to access the VSV after removing the intake brace, with no luck. I don't have small dainty hands or huge ones for that matter. I went ahead and removed the TB instead, and that IS definitely the way to go, as you have clear view of the VSV and all the hoses going to it. I can't imagine trying to remove it any other way.

The CEL code finally cleared itself out this morning, after the 3rd startup (commute, to/from home to work).

To sum it up, EGR Modulator replaced a few years ago, EGR valve changed a few months ago & finally the VSV. The code went away for a few months after changing the Modulator, but not after the EGR valve replacement.

Let's see how long this lasts, as I don't think my sensor can be bad.

Thanks for all the help!

 

[Beowulf]

Now I'm ready for some closure to our P0401 problems... Let's see how long this lasts, as I don't think my sensor can be bad.

Stick a meter on the old VSV for EGR and see what ya get. I did about the same as you several years ago... Cleaned EGR modulator.... wait ... cleaned EGR temp sensor ... wait.... replaced EGR modulator ... wait .... Cleaned EGR valve .... wait .... Cleaned it again .... wait ... Replaced EGR Valve .... wait .... Replaced VSV and Viola! VSV metered bad. P0401 gone. Screwed around with that thing for 18 months.

-B-

 

[GXO]

funny, I just swapped out my EGR VM today. The filter was black...then I realized that one of the two ports on the side was CRACKED OFF, but held in place by the tension of the still plyable vacuum hose and the vacuum itself.

Poor thing was sniffing engine compartment for all this time

New VM in place, idles better, etc.

Cleared the P0401 and crossing my fingers