P0401 - EGR flow insufficient – HOW TO…
01-05-09, 04:40 PM
#17
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How to diagnose and replace a failed EGR vacuum modulator.
Looks like P0401 is a common problem on ’92-’96 ES300.
I just fixed mine after doing some research on the forum.
All the information is out there but it’s all scattered and unclear.
I decided to put it all together in one place and throw in some pictures for DIY.
So you have P0401, which states for EGR insufficient flow.
Most likely you will find the problem by checking:
1. EGR Valve
2. EGR Vacuum Modulator
3. Vacuum hoses
It’s easy and I am going to explain how to do it. Read on below.
But if by checking things outlined above you could not find the problem,
then there aren’t many thing left to check: EGR gas temperature sensor and VSV.
But I didn’t have to do it and most likely neither will you.
So, here is what we’re looking for under the hood:
Looks like P0401 is a common problem on ’92-’96 ES300.
I just fixed mine after doing some research on the forum.
All the information is out there but it’s all scattered and unclear.
I decided to put it all together in one place and throw in some pictures for DIY.
So you have P0401, which states for EGR insufficient flow.
Most likely you will find the problem by checking:
1. EGR Valve
2. EGR Vacuum Modulator
3. Vacuum hoses
It’s easy and I am going to explain how to do it. Read on below.
But if by checking things outlined above you could not find the problem,
then there aren’t many thing left to check: EGR gas temperature sensor and VSV.
But I didn’t have to do it and most likely neither will you.
So, here is what we’re looking for under the hood:
I would appreciate any help you can give.
thanx very much,
jim
10-09-09, 09:19 PM
#18
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how long do you have to apply vacuum for the valve while the engine is running? is it instantaneous that the car will react to it? also what can you do if the valve isnt responding to vacuum? last thing can you open the modulator without breaking it to see if the diaphragm is broken? thanks for any inputs.
01-12-10, 05:25 PM
#21
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Thanks, this is great! My '96 ES is displaying this code. This helps sooo much!! I just replaced the modulator on mine. It worked like a charm!!! Thanks again!!!
Last edited by rattler96; 03-03-10 at 05:00 PM.
03-11-11, 08:39 AM
#23
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This article is awesome. I had basically decided to ignore th check engine light due to the p0401 error.
This post quickly showed the problem to be the vacuum modulator as well and a quick search from the number on the valve led me to a new toyota part on ebay for 45.88 delivered!
Thanks for taking the time to write this up, especially with photos.
This post quickly showed the problem to be the vacuum modulator as well and a quick search from the number on the valve led me to a new toyota part on ebay for 45.88 delivered!
Thanks for taking the time to write this up, especially with photos.
03-15-11, 07:53 PM
#25
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I guess I should of searched forum before posting basically the same general info on a sticky yesterday but Pon-Alex shows perfectly what info I found and used on my 96 Camry and now my 96 ES300...his instructions and pictures are perfect! I wish I would have found this but I added how to test the VSV that effects the EGR system I'll go to sticky and copy links and add it here.
Last edited by VicsIS350; 03-15-11 at 07:58 PM.
03-15-11, 07:57 PM
#26
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