Probably a silly question, but here it goes anyway.

If you replace the Mass Air Flow on a 2000-2001 Maxima, do you have to flash/reprogram the ECU?

Separate question: If you replace the IACV, do you have to flash/reprogram the ECU?

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Background: I'm having the ECU repaired / flashed and shipped back to me. I'm also purchasing a new IACV and MAF. So, I'm trying to figure out whether the car, with with the new IACV and MAF on it, will have to be flashed / programmed again "with them all mounted and together."

I should know this, as it's my second time through this process in a year. Overall, the car seems to be running fine, but it recently threw the P0505 code and gave off the electronic burned smell (most likely the ECU). So replacing all three.

 

No - read this thread; https://maxima.org/forums/5th-genera...axima-t-2.html

 

No need to change the MAF sensor. P0505 code is bad circuit for IAC and ECM. And you only need to re-flash the ECM if your swapping in a different one.

 

The above statement is not quite correct. The correct statement is:

When you install a new IACV, do the following :

• Before installing: Make sure that the ECM has not been damaged by the old/bad IACV. In particular, the STA509A transistor in the ECM is typically damaged when the IACV fails. A damaged ECM will typically not damage a new IACV, unless the ECM has been damaged in some catastrophic way (shorted or melted tracks, etc.). Bottom line: Only install the new IACV after ensuring that the ECU has not been damaged in a catastrophic way.
• After installing the IACV: With 3.0L engines, disconnect the battery overnight. No need to do idle re-learn. With 3.5L engines, you may have to do idle re-learn to stabilize your idle RPM.