Insufficient air flow

[aznstylez]

has anyone have this problem before. My dad's 99' Avalon check engine came on with the code. I was wondering what had to be done? The car has almost 202,000 miles on it. Thanks in advance.

[aigochamaloh]

insufficient air flow? normal air flowing past the air filter?

check the air filter, make sure it's clean. make sure your vaccuum lines are hooked up correctly.

if it's insufficient egr gas flow, then clean your egr tube and the filter on top of the egr modulator...

[aznstylez]

the engine code is P0401. where is the egr modulator? I had the car checked at Autozone. I asked the dude could it be the air filter, he said nope. It is dirty though.

[aigochamaloh]

so it is the egr flow insufficient code...

the modulator is connected to the egr valve with a rubber hose. it should be mounted very closely to it. you can find it in my picture mounted to the firewall as i had nowhere to mount it with the supercharger installed. it has two hoses on one side, and one more on the opposite side. yours may or may not have a top that pops off with a filter inside. it might be that the newer engines don't have this filter.

my suspicion is that it could be a vaccuum line though. double check all the vaccuum lines with the diagram on the hood, and make sure the lines are all in good condition. i've had this error code and it happened when the egr modulator was just not hooked up to a vaccuum line.

[aznstylez]

Thanks for your response, now all I have to do is convince my dad to let me touch the engine, hehehe. I'm in my 20's and he doesn't trust me. Oh yeah, another question. Have you ever have a problem with the stabilizer link/end link being loose? Couldn't it just be tighten up?

[toyomoho]

The computer states the manifold absolute pressure is larger then expected when the EGR system should be on. Hence the EGR system is not working as it should be.

EGR valve could be stuck closed or the pipe the runs the gases to it plugged up. These items can be cleaned. A problem with VSV or EGR valve malfunctioning. Open or short in EGR VSV electrical circuit (can test this with a volt/ohm meter), vacuum hose leak/plugged to VSV or EGR, MAP sensor or ECM. If the car runs OK doubt the last two are the problem.

Do a TN history search as this same code question just came up.

Download the 2000 Avalon manual at the link below, should be close enough to help you.

http://d01.megashares.com/?d01=badd2e4

If no help, you can download the Gen_4 Camry manual from the site below. The two cars use the same V6 engine. Download the Diagnostics Section.

http://oregonstate.edu/~tongt/camry

[stevehosun]

When I had P401 code in Camry, I cleaned carbon from the EGR valve by carb cleaner.
Turn engine on to make sure EGR pipe from engine block is not clogged. Put EGR valve back into place.

Then reset CPU. Drive few days. Still P401 returned. At this point, I replaced EGR modulator-- UFO like disk with Vac line. Then it never comes back so far. OBD II reader shows nothing.

You need OBD II reader to keep track of CPU. Otherwise it is guessing game.

[aznstylez]

Originally Posted by stevehosun

When I had P401 code in Camry, I cleaned carbon from the EGR valve by carb cleaner.
Turn engine on to make sure EGR pipe from engine block is not clogged. Put EGR valve back into place.

Then reset CPU. Drive few days. Still P401 returned. At this point, I replaced EGR modulator-- UFO like disk with Vac line. Then it never comes back so far. OBD II reader shows nothing.

You need OBD II reader to keep track of CPU. Otherwise it is guessing game.

Huh, you replaced the EGR Modulator with Vac Line? Where did you get the Vac Line? Do you have a pic of what you did? The car runs fine, it picks up fast. Thanks in advance. Most appreciates to all the answers.

[stevehosun]

P401 does not affect your car performance barely-- it just decrease O2 into combustion to decrease NO by lowering temperature-- and increase life of catalyst.
In my case, EGR modulator- but yours may be different since there are several components involved....