EGR Flow CEL AGAIN. (1 Viewer)

[madams557]

Okay, a few months ago I posted that I had a check engine light come on and the code reflected EGR Flow insufficient. Took the truck to the dealership, they ran the code, and came back to me to say they found no problem and reset the light.

Now the light came on again.

Both times this light has come on I have made a quick round trip drive to Denver and back at 75 miles one way. Normally I drive about 2 miles to work and the light doesn't come on. I hit the road and the light comes on within 15 miles of the house.

Anyway, so I pull into the dealership at 4:30 with an hour left before the mechanics go home, just so that a CEL code can be found. Again, EGR flow insufficient.

My first question is - Does hooking up the computer to check the code reset the CEL codes? Because after he ran the diagnostics, the check engine light wasn't on but I didn't see the mechanic pull the plug to do it.

Second, he disconnected the three vacuum hoses running in and out of the modular. He said that their was vacuum going INTO the modular but not coming OUT of the modular and from his quick look suggested a new EGR modular should be on my Christmas list. So my question is by spending the money to replace the modular, will I solve this problem or is it only a band aid?

Michael

 

[Beowulf]

My first question is - Does hooking up the computer to check the code reset the CEL codes?

The mechanic has the option of resetting the MIL (check engine light) or not.

So my question is by spending the money to replace the modular, will I solve this problem or is it only a band aid?

Michael,
As you were told in the first thread on this topic, there is no single "fix" for the P0401 code (EGR flow insufficient). If the mechanic has successfully isolated the problem to the EGR modulator and eliminated the other components as a cause, then replacing the EGR modulator will fix the P0401. If the mechanic is guessing (and I suspect he is) then you will not fix the problem and it will return in a few months.

Go back and read all of the repsonses in your first CEL thread. You got a lot of good advice on how to address the P0401. You were also told that it would probably come back.

I am repeating one of the points that was made in the first thread but you should be aware that the P0401 is a 2 trip logic; and "trip" is defined as a "drive cycle." A drive cycle is getting the vehicle up to a certain speed (50 MPH?), the coolant reaching a minimum temperature (i.e. warmed up), and maintaining the minimum speed for a specified time ( 5 min ?) I can't recall all of the drive cycle details but Gumby posted an explanation if you want to search the archives for the exact combo. So basically, your 2 mile commute will not trip the code and the MIL will not be set. You could drive for weeks and not get the code in two successive trips (i.e. 2 trip logic.)

FYI, don't pay anyone to replace the EGR modulator. It doesn't require any tools; just attach the hoses like the old one and pop it into the spring. 1/10 th banana. Before you buy one (from C-Dan I hope!) you should check the filter as Semlin suggested.

HTH.

-B-

 

[landtank]

That was nice of you -B-, I had put this thread in the ignore column.

 

[turbocruiser]

Yes, very nice of you B, maddams, many here, including myself, have had the pleasure of "fixing" the EGR system several times just to have the code come back. Everything B told you was totally correct and I would heed his advice as well as the advice all around here on the EGR system in general and the PO401 in specific. In my particular case, my modulator was bad which I determined by using the FSM diagnostic procedure, then my VSV was bad which I determined by yanking it out and smashing it to smithereens!!! Seriously, no one intends to sound rude to you its just that we have worked around and dicked around on our own rigs long enough with this problem to know that one rig's problem is not always the other rig's problem, and to also know that this particular problem really requires lots of lonely hours of researching. In my humbling case, I listened carefully to CruiserDan who told me not to prematurely report that the PO401 was cured cause that was sure to screw things up again!!! So I waited a little while, reported with pride that I had fixed my 401, (not long enough apparently for two good trip cycles) and sure as snot, that damn code kept coming back until I fixed the friggin problem and admitted my error. It wont go away till you fix the problem.

Some info for your info, the consensus around here is that the EGR system on our rigs is overly sensitive and a pain in the ass to fix. Also, there is no real damage to anything as a result of the EGR flow insufficient, I mention this in case you are thinking to yourself that you have run it this way for a long long long time, which you probably have. The way you are using your rig your EGR is rarely in action anyway, it is flowing more at highway speeds when you are not accelerating so your short commutes are not helping you cure this thing, but, on the other hand, they are not hurting your rig really either. Still, get it fixed so you can pass emissions whenever they are due again. HTH.

 

[madams557]

I do apologizing for bringing this up again and I do hold the members of this board in great regard. I only mentioned it because I got the impression from the mechanic that replacing the modular would be the solve all and that contridicted was I had read.

I reposted because I wanted to confirm the conditions which triggered the CEL, and I didn't read anything on that from the first post on the subject.

I was also hoping that I wound receive confirmation that I might be receive a line of crap from the dealership that a modular replacement would be the end all.

From my last post on the matter, I made a print of everyones comments and have saved it in a hardcopy form when the time comes for me to work on the problem. I say this because I don't want anyone to think that I'm slacking in my responsibilities as a forum member in researching before I post. I apologize if I have left that impression.

 

[Beowulf]

I don't want anyone to think that I'm slacking in my responsibilities as a forum member in researching before I post. I apologize if I have left that impression.

No problem Michael and keep this thread alive as you work through the problem. As far as OBD codes go the P0401, and the pre-OBD-II equivalent, is fairly common and we try to give guidance and understand what guys are doing to fix the problem. The more feedback we get the better we can help the next guy.

-B-

 

[Junk]

Michael,
What no one has told you (since I am the only one with this far superior knowledge ) is that the P0401 code is a special code in the FZJ80. It means that your 80 is parked too close to a 45 long bed and that it has resulted in the 80 developing an allergy to the 45. So send me your long bed and next time you fix the EGR system it will be fine .

B's comments about the 2 trip logic are spot on. I think it's 45 MPH and maintaining that speed for a few minutes.

While others will disagree, to me, the best way to fix the P0401 code is to just bite bullet and replace the EGR valve, VSV and modulator in one clean shot. If not, you'll likely just be chasing it for a long time.

 

[madams557]

Junk,

Is there another Land Cruiser that I can get which will offset the allergeric effects of the FJ45? For instance, if I was to import an BJ70 and park it between the FJ45 and FZJ80, would that help block the effect of the FJ45?

Your last comments about replacing the whole gambit was sort of what I was asking about. So I've added the EGR modular replacement to my 'To Do" list.