What could be next thing cause EGR system fail.? Code p 401. on 1997 Toyota Camry

I checked EGR valve ,replaced EGR modulator and vaccum switch valve. But engime light still on after running for couple miles.Some one know about this give me advice what is the possible part cause this problem.Thanks e.

by in Renton, WA on April 02, 2012
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1 answer
ANSWER by , April 02, 2012
The things that need to be checked and items that can cause this code are listed. Engine Control Module (ECM) Restricted Exhaust Gas Recirculation (EGR) Passages Dirty Throttle Body Vacuum Modulator Vacuum Switching Valve