1997 throwing a P0401 code (EGR)- what to do? (1 Viewer)

[Lancruza]

I pulled the cap off of my modulator and it's full of carbon. So I could replace the modulator for like $75-80 or I've been reading that some people get rid of the EGR setup and block it off or since the modulator is blocked , the EGR system is not working, I could just continue to drive as is. Thoughts? What would you do?

 

[davidp14]

I got a Toyota egr modulator from Ebay for about $20. It fixed my p0401....for about a month


You will likely need to pull the entire system and clean it. Replace all vacuum lines as well. Or, just buy some keychains and test module like I did.

 

[voodu3]

X2 on the keychains

 

[greentruck]

I punch a few buttons on my ScanGauge and make the Check Engine light go away.

 

[Tools R Us]

I just "fix" them with a 4.7K ohm resister.

 

[Lancruza]

What do you mean by "keychains" and "test module" I'm on the uninformed side over here. Enlighten me. I've got an OBDII scanner tool that can turn the CEL off, but I'm sure it will come back on. Not really worried about the light. I just don't want to do any damage.

 

[LC4LIFE]

Lots of reading here on the "fix" and some links to other info about it all. EGR Temp Sensor Test Plug

 

[Lancruza]

Shoo weee! Lot's of reading is right. Thanks LC4 for the info and link to more links.

 

[greentruck]

You won't be harming anything on the truck by resetting the code to make it go away. I may get it just as the truck reaches full operating temp, then it's gone for the day. The worst that can happen is that it may come back as ours does.

 

[BILT4ME]

I recently got on the interstate and ran my truck for 5 hours and I had a P0401 code that popped up while I was driving. Sometimes, when a vehicle has been driven around town and not REALLY heated up and driven, then sensors can get "unclogged" or heated to the point where the oily goo burns off, or all the moisture burns out of the oil.

I cleared my light with my Ultragauge while I was driving and it never came back on the rest of my 1200 mile trip.

 

[Lancruza]

You won't be harming anything on the truck by resetting the code to make it go away. I may get it just as the truck reaches full operating temp, then it's gone for the day. The worst that can happen is that it may come back as ours does.

Hey, thanks. I wasn't worried about hurting the truck by turning the CEL off. I was wanting to make sure that it wasn't going to be bad for the LC if I drove it while there was an EGR issue going on.

 

[Tools R Us]

Hey, thanks. I wasn't worried about hurting the truck by turning the CEL off. I was wanting to make sure that it wasn't going to be bad for the LC if I drove it while there was an EGR issue going on.

As long as it runs well, doesn't have a vacuum leak, the valve isn't stuck open (rare), ect, good to go. If the modulator diaphragm is perforated (common), best to plug the vacuum lines, BBs in the lines or remove and cap.

 

[Lancruza]

As long as it runs well, doesn't have a vacuum leak, the valve isn't stuck open (rare), ect, good to go. If the modulator diaphragm is perforated (common), best to plug the vacuum lines, BBs in the lines or remove and cap.

Thanks. Any need to pull the EGR and put a plate cover over where it mounts and where the pipe goes in? I'm guessing that it would be OK to leave the EGR mounted and just cap off those vacuum lines also.

 

[BILT4ME]

What do you mean by "keychains" and "test module" I'm on the uninformed side over here. Enlighten me. I've got an OBDII scanner tool that can turn the CEL off, but I'm sure it will come back on. Not really worried about the light. I just don't want to do any damage.

Go to Absolute Wit's End.com for keychains. Here's a hit:they double as block-off plates......

@NLXTACY

 

[Tools R Us]

Thanks. Any need to pull the EGR and put a plate cover over where it mounts and where the pipe goes in? I'm guessing that it would be OK to leave the EGR mounted and just cap off those vacuum lines also.

No need to remove, if it doesn't leak, most don't, if it doesn't get vacuum, wont open, so blocked. Can remove the whole thing, makes it a little cleaner, but that is a pain of a job.

 

[vegasfj40]

Why not get a FSM and repair it? I had the code when I bought mine and was able to fix the problem. Its not too complicated with the diagnostic procedure in the manual. I actually had a couple of issues but was able to fix them. Havent had the CEL now for 2 years.

 

[Lancruza]

Why not get a FSM and repair it? I had the code when I bought mine and was able to fix the problem. Its not too complicated with the diagnostic procedure in the manual. I actually had a couple of issues but was able to fix them. Havent had the CEL now for 2 years.

Yep, that is definitely an option. I've read of a slight increase in mpg without the EGR in place. I also read that lots of people do away with the EGR...one less thing to go wrong. I'm reviewing all options. Options are good.

 

[vegasfj40]

I can tell you in my case, when the egr wasn't working properly my combustion temps were higher and as a result I would get an off idle ping. The egr actually helps to cool combustion temps. As soon as I repaired the system my detonation was gone. The fuel mapping in the computer is probably programmed for EGR as well. I know there are overseas versions of the 1FZ that don't use EGR but I would bet the computer programming used there is designed for that.

 

[Lancruza]

Go to Absolute Wit's End.com for keychains. Here's a hit:they double as block-off plates......

@NLXTACY

Hey, thanks for the link and the info. That wits-end site is awesome. I was unaware of that site. They have lots of great stuff on there.

 

[Lancruza]

I can tell you in my case, when the egr wasn't working properly my combustion temps were higher and as a result I would get an off idle ping. The egr actually helps to cool combustion temps. As soon as I repaired the system my detonation was gone. The fuel mapping in the computer is probably programmed for EGR as well. I know there are overseas versions of the 1FZ that don't use EGR but I would bet the computer programming used there is designed for that.

Interesting...I've not heard anyone say that their LC ran worse after deleting the EGR. I know that these computers learn and compensate but I'm not sure to what degree. Most of what I've read states that temps were cooler when getting rid of the EGR. Most intakes like a cooler air temp. EGR has never made much sense to me from a performance or economy perspective, but I'm no engineer either.