P0401 Engine Code - 2000 Camry

[louye2]

My 2000 Camry (4 cylinder, automatic, 150K) has the check engine light on. I read the code via Autozone's scanner and the error code is P0401 (insufficient EGR air flow). I have read all the other posts on this topic and religiously followed the advice on cleaning all EGR-related hoses, orifices, EGR modulator filter and metal EGR pipe. I also performed all the various EGR vacuum tests listed in the Haynes manual for this car:

- Passed EGR vacuum test (pull vacuum on EGR valve, engine stalls).
- Passed EGR vacuum modulator tests (block R & P, verify air flow; block R & P, set RPM to 2500, verify air flow resistance).
- Passed all EGR system tests with a T-connector and vacuum gauge between the EGR & VSV and TE1 & E1 connected.
- Passed VSV for EGR tests (resistance test, continuity test, air port E & G test, port E flow with 12 V applied.

I took a chance and diagnosed the cause as an intermittent issue with the VSV for EGR and replaced it. The P0401 still returns after driving for a few days. I could just replace the EGR ($160) and EGR vacuum modulator ($80), and pray to the Camry gods for the miracle cure, but that does not make sense given all the diagnostics I have already done. I'm at a loss on what to do next.

Would someone please advise me on this one? Are there other parts I should be testing like the MAP sensor? Thank you in advance for your help.

[toyomoho]

Send a private message with an email address, will reply with more service info.

Could be the MAP but you can test this before replacing.

[c_sal]

I have a 2000 camry 4 cyl with 50K miles, check engine light came on. Read posts that said to check gas gap for tightness. I did and it was loose. tightened and light went off a day later. Not sure this applies to your situation but it is an easy thing to check.

[00ES300]

sorry to kinda bring a post back from the semi-dead. But this is happening to my camry as well. Its a 2001 with about 75k on the clock.

The CEL came on and it scanned egr insufficent flow. I went ahead and replaced the egr valve w/o thinkin about it. Stupid me

Light came back on tonight and I'm gonna take it in tomorrow to have it scanned. I work at a non-toyota dealer so I have access to the scan tools for free

I should also check my MAP sensor and perform all those checks you did as well. Ill let you know if I find the cure.

Keep us posted as well

[louye2]

The check engine light went out a few weeks ago and has not returned. I did check my gas cap and have been focusing on turning it tightly when I fill up the tank. Perhaps the gas cap O-ring is worn and should be replaced. I'll keep y'all posted.

[a1475]

I have a Toyota Camry CE 2000 model. The engine check light has come on. The code it gives is P0401 that translates to Insufficient EGR flow. However, my car is running just fine. There is no change in whatsoever can be observed while driving.

The engine check light came on (on day one) after I pressed the brake paddle for several times while car was parked and ignition was off.

Though, the light went off automatically (on day two), and then I drove almost 50 miles. But on day three it came on again. All automatically. And it has been on since then.

Can you suggest how to fix the problem. I am from Ames, Iowa. Do you know a good mechanic who can fix the problem.

Waiting your earliest reply.

Thanks,

[groovemasterodi]

Maybe clean the EGR valve? Check out the DIYs.. also maybe check exhaust gaskets and such. Good luck!

[a1475]

Do you think that the Engine Tune-up will take care of this problem?