2.7L auto weak with error code p0402 "EGR EXCESSIVE FLOW"

I also have a 99 Prerunner 2.7 with the same darn code. I have replaced the egr, tested the modulator, replaced ALL vacuum lines I went behind my self to double check that they were all in the right spot and on good as well. Now there has not been any power loss at all or smoke I have had this truck since 1999 and have kept it up well. No mods all factory. After I replaced the EGR and hoses I reset the light drove from Roanoke VA to Winston-Salem NC and back around 250 miles before it came back on with the same damn code. Like I said it still runs great no smoke or power loss. Does anyone know the best way to test the vsv, pwm and the obd? my next step is to test those along with the temp sensor.

 

Steve - can you tell me exactly where the vacuum switching valve is. I also have a 3rz and I have replaced the egr valve and the temp sensor and the P0402 code still comes on. I do not have any loss of power. I appreciate it if you can take some pictures of the location. Thanks!

 

this is what to look for. but that is for the OPs 99 2.7. not sure if they have the exact same one for your truck.

check rock auto to see what yours should look like.

 

I changed my VCV/VSV however you may refer to it, code still comes back on. Factory EGR valve functions after simple vacuum test. Would replacing my exhaust system which is rusting out help? It can't possibly hurt... This seems to be a common problem now for our Tacomas. Mine has 160k on it now.