PO401 Code - Toyota Nation Forum : Toyota Car and Truck Forums

Chris Crash · 12-16-2008, 11:02 PM

97 Camry CE 4-cyl manual with a PO401(I think) code. Scan tool said "EGR valve insufficient flow".

I checked all the vacuum lines, all are hooked up and clean. The EGR valve itself is clean and working properly. Where the EGR valve goes into the plenum is clean too.

What else should I be looking for?

***new echo owner*** · 12-17-2008, 12:45 AM

EGR VSV underneath the intake. Are you sure that you are getting vacuum to the EGR valve when it is supposed to?

N.E.O.

***toyomoho*** · 12-17-2008, 12:46 AM

Have you checked the VSV valve that controls the EGR valve.

darican305 · 12-17-2008, 06:48 AM

i had this same code for a year and i finally got it fixed and with my luck it was an under 100 dollar fix. what did was go to autozone and i bought the vaccum modulater and i bought 4 feet of new vaccum lines installed everything reset the check light and wala its been 2months and code free. give it a shot you can always return it if it dont work.

Chris Crash · 12-17-2008, 10:06 AM

Quote:

Originally Posted by new echo owner

EGR VSV underneath the intake. Are you sure that you are getting vacuum to the EGR valve when it is supposed to?

N.E.O.

How would I check this?

Chris Crash · 12-17-2008, 10:06 AM

Quote:

Originally Posted by toyomoho

Have you checked the VSV valve that controls the EGR valve.

Where is the VSV valve and how do I check it?

***new echo owner*** · 12-17-2008, 10:25 AM

After the engine is warmed up, just pull the vacuum hose off at the EGR valve and check for vaccum there while revving the engine up. Download a copy of of the FSM, page 42: http://camrystuff.com/manuals/Gen4/SFI.pdf

The VSV is bolted on the engine underneath the intake manifold.

N.E.O.

Chris Crash · 12-17-2008, 10:59 AM

Do you mean the vacuum hose that goes right to the bottom of the EGR? It's a pretty big one held on with a flange and two bolts?

Chris Crash · 12-17-2008, 11:04 AM

To get to the VSV, would it be easier to put the car on a lift and get it from below or take the intake off?

***new echo owner*** · 12-17-2008, 11:14 AM

Quote:

Originally Posted by Chris Crash

Do you mean the vacuum hose that goes right to the bottom of the EGR? It's a pretty big one held on with a flange and two bolts?

No, the small rubber hose that goes to the top of the EGR valve.

It is indeed a little easier to get to the VSV when the car is on a hoist, that is if that is the problem. It was just a suggestion that the VSV maybe the problem, you still need to test the circuit to verify first.

N.E.O.

Chris Crash · 12-18-2008, 11:29 AM

Alright. Thanks for your advice. I'll check the vacuum today and tomorrow I'll rip the VSV off and check it out.

Thanks a lot.

Sparkey · 12-18-2008, 12:04 PM

i am having this same p0401 issue and the car is running just fine. is there a way i can tell if it is the VSV or the modulator or is that just a trial and error situation? ive already lost $200 when it failed inspection and the asshole told me he was POSITIVE the EGR itself was the trouble....a week later here i am with the same issue.

***toyomoho*** · 12-18-2008, 12:13 PM

What year and engine type?

Sparkey · 12-18-2008, 01:57 PM

2001 4banger (2.2L i think)

*if i have the car running and rev it up i get vacuum at the EGR but the EGR shifts only for about 1second. is there maybe not enough vacuum to maintain its shifted state?

Chris Crash · 12-18-2008, 05:57 PM

Quote:

Originally Posted by Sparkey

2001 4banger (2.2L i think)

*if i have the car running and rev it up i get vacuum at the EGR but the EGR shifts only for about 1second. is there maybe not enough vacuum to maintain its shifted state?

We essentially have the same engine and problem, so I would just check all the things that were previously stated.