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Ask Ted Ritter Your Own Question
Ted Ritter
Ted Ritter, Toyota Master Tech
Category: Toyota
Satisfied Customers: 4304
Experience:  Toyota Master Tech, ASE Certified
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1997 Toyota Camry Check engine light on, code P0401. Replaced

Customer Question

1997 Toyota Camry Check engine light on, code P0401. Replaced EGR valve and all vaccum hoses. Check engine light still on showing same code. Could it be map or vsv?
Submitted: 6 years ago.
Category: Toyota
Expert:  Matt J replied 6 years ago.
Chat Conversation Started
Matt J :

Hello my name is XXXXX XXXXX I will be more than happy to assist you.

Matt J :

Yes the VSV is normally the cause for that code. If you have a volt meter and a vacuum hand pump I can show you how to test it

Customer :

I don't right now, but could get one tomorrow or the next day

Matt J :

Here is the test procedure to see if the VSV is the cause.

Full Size Image

Customer :

Am I checking the vsv or the vps

Matt J :

you are checking the VSV

Matt J :

the VPS and VSV are the same thing

Customer :

Is the vav for the egr located on the front of the motor or on the fire wall

Customer :

heyy

Expert:  Matt J replied 6 years ago.
the vsv is on the on the drives side
Expert:  Ted Ritter replied 6 years ago.

The illustration in the above answer is for checking the MAP sensor which has nothing to do with the P0401 trouble code, although the EGR vsv can be the problem because they can have intermittent problems the most common cause for the 401 code is the EGR vacuum modulator valve which is connected directly to the EGR valve by a spring bracket and has three small vacuum hoses and an exhaust back pressure hose on the bottom. The modulator valve has a plastic cover on top, remove this cover, there is a fiber filter inside, remove this filter and check to see if there are any burned spots , if so replace this valve.