Code P401 came on at inspection. chg EGr valve and modulator. Check engine lite keeps coming back on HELP

You may just want to check your gas cap also and make sure there is not any air coming through or it will throw off the sensor. Just a quick cheap check.

I change toe gas cap. Now my gas tank has a positive pressure, but the light is still on. I try to trace the leak in the gas line and in the emission to the carbon vapor trap container. So far, it is not successful. The shop did not really fix this problem. I already waste time and money at the dealer. I would like to hear any successful from the Toyota Camry owners.

I changed the EGR modulator, removed cleaned the EGR valve and found the VSV switch moved the tubes so it didn't pinch. I found the EGR mod on Ebay for $25, valve gasket $3 at auto parts store, and new hoses for $3. I have 159,000 miles and needed to register the car but it failed due to D401 code. I took my time and went step by step. The VSV is in a hard place but lift the car, put on blocks and shimmed under the car, located the hose to VSV and moved them. If your VSV is bad buy it on Ebay used for $25, I didn't need to but almost bought. We'll see in a few days if I need to replace the VSV switch but for now the "Engine light" is and I can register now.

Check your gas cap. I changed mine out and then it passed inspection. Sometimes this resolution is completely overlooked.

Hi. You need to change the gas cap original You can go to Toyota Dealer and they turn off lights after set the gas cap. Good Luck