Dreaded P0402 Code

[mtrdud]

The CEL on my daughters 99 PreRunner (2.7) came on a couple of weeks ago. I scanned it and got the P0402 code. I found that the cast manifold was slightly cracked and I replaced it with the later tube style mini header. I reset the light and CEL came back after two days. Suggestions on what to check next? The truck is running fine btw.
Thanks

 

[mtrdud]

BTW - the code says EXCESSIVE EGR FLOW and a pending EXCESSIVE EGR FLOW.

 

[thzpcs]

Apparently it can be caused by a couple of things. Initially, I'd believe that the N75 EGR valve is busted, but it can also be caused by a dirty MAF sensor as well. I'd take a look at cleaning the MAF sensor, then looking into replacing the EGR valve if it doesn't go away.

 

[occruiser]

My dad's 05 Tacoma was sending the same message. He swapped the sensor with a new one I ordered him from rockauto.com. It was a denso and ran about 38 bucks. Problem solved.

 

[mtrdud]

My dad's 05 Tacoma was sending the same message. He swapped the sensor with a new one I ordered him from rockauto.com. It was a denso and ran about 38 bucks. Problem solved.

Which sensor?