Ok I will start with the hose. Why do you say not to touch the sensor? Do you just mean don’t mess with it unless the hose replacement doesn’t work?
I actually just got into my car and the service engine light went out lol. I’m sure it will eventually come back on. It has been constantly illuminated the last couple of weeks.
Because it’s very possible that the hose is the sole cause of the problem, and replacing the sensor would therefore be a waste of money.
That sensor is very expensive from Nissan and you have to get the computer to reprogram itself to get used tot he new sensor. The MAF measures all the air entering the intake manifold. If the duct is letting in air after the sensor, then all the air is not being accounted for and it will throw a code for a bad sensor even when the sensor is good.
Most of the time the sensor is actually at fault, it is because it is dirty. It is easy to clean with a spray cleaner. DO NOT use any type of brush or cloth on the sensors elements or you will damage them. Just a little cleaner sprayed on them is enough.
If you have a aluminum foil adhesive tape used to seal HVAC duct seams, a piece of that can seal the hole in your duct, at least temporarily to determine if that is all you need.
He has P0101:
If his air induction boot is leaking, it will explain the code and expensive MAF replacement is not needed, at leas at this point, I’m 100% with @keith on this.
If boot was leaking, it is not far-fetched to guess that some dirt might have contaminated fragile MAF, so $7 MAF cleaner aerosol can is good invstment into “hey, maybe MAF can be saved?” attempt.
One more thing: on Nissans (at least of that era), the standard procedure to calibrate Air/Fuel Ratio and Idle Air is to DISCONNECT MAF and make car throw the P0101, then clean it and let car re-learn by itself over 20 minutes or so of idling. Check exact procedure on nissanhelp.com 
So, for me the whole repair looks like a trip to the dealer’ part department to get new boot, then stop at autostore to get MAF cleaner can, then a screwdriver and code reader and under hour to do it all. I do not get paid $900 an hour 
Those prices look reasonable to me for dealership work. If they fixed the problem I think your are good to go. The torn boot must be replaced, no doubt about that. Was the MAF replaced also? Or just diagnosed & serviced? As mentioned above to know more about this we’d have to see the labor and parts breakdown.
Some mechanics want to replace all of the parts that could cause the problem to cover all bases and prevent a “come back”, with sufficient skill, experience and confidence they should be able to identify the failed part, the leaking air induction hose.
My bad, I saw P001 under the induction cleaning on the quote and thought I saw P0001. Having a little trouble with a cataract forming in one eye so sometimes I don’t see clearly. They made a typo and I misread it.
I knew all the others were P0101.
Just because I do not know, how long will it take if a new boot is put on to see if it was the problem, or is it a clear codes and wait?
I do not know if P0101 would clear itself upon few drive-cycles or if it needs to be cleared.
I do know that for Nissan after owner replaces the boot and/or clean MAF he has to warm up the car, disconnect MAF, start it and let P0101 set again, stop, clear the code, idle warmed up car for 20+ minutes and it will successfully finish calibrating air intake for idle air volume.
The air intake boot developing cracks over time is normal. Not sure why Nissan wants a fortune for what is basically a rubber bellow, but you can get a Dorman direct fit one for $35. (DORMAN 696085) A hole in it lets in unmetered air into the intake as its after the MAF. Regarding the MAF as others have pointed out, usually a cleaning is sufficient with proper MAF spray cleaner. The price Nissan is charging is for the whole assembly, and there is zero reason to buy that. Again if you want to replace RockAuto sells one for your vehicle from Hitachi that would be the same as the OE part. You need a torque safety bit to remove the sensor from its housing to replace it or to clean it. Again the replacement cost at RA is $77 for what is the OE part. HITACHI MAF0031
As for the ECU or ECM programming, its not needed other than to clear the code. You can buy cheap code readers on Amazon for less than $20 that will do that just fine. There is no relearning required here unless you disconnect the throttle body. As for the induction cleaning, I would not bother unless you notice the car continues to run really rough. The PCV will allow more gunk to get into the air intake manifold than a small crack on the bottom of the intake hose.
To summarize they would charge you over 900 for stuff you can buy for a bit over 100. It does not require much in terms of tools or time. Easily accessible stuff.
If you go to a pick and pull junk yard the parts would be less than $20. The air intake hose is the same as on all Altimas from 2007 to 2013. As for the MAF, it is a widely used part on many Nissan and Infiniti models, but the easiest and cheapest will be to just buy a can of MAF cleaner, remove yours and spray it clean.
Its the actual hole in your intake hose that is causing the code, if you don’t want to buy a code reader, the malfunction indicator light should go off on its own after a couple of days once the issue is fixed. There is also a manual method using the key and accelerator pedal to retrieve and clear codes that you could lookup.
Wow thank for all of the great info here! I really appreciate it… And everyone else’s input
The link below takes you to your suggested dormant hose on Amazon. It says it is not compatible with my 2012 Nissan Altima Coupe.
You can’t always trust Amazon’s fitment database.
If you have the 2.5L 4-cyl. engine, that Dorman part is correct, according to Dorman.
If you have the 6-cyl., Dorman doesn’t show a hose for that.
I am assuming you have the 2.5 4 cylinders. It is a different part if you have the 3.5. Correct part number for that is 16576-JA100. Its less expensive than for the 4 cyl. Here is a link for one for the VQ35 6 cylinder
https://www.tascaparts.com/oem-parts/nissan-upper-duct-16576ja100
Order the right one for yours and replace it. You will notice the improvement in your engine.
How do you tell if the induction hose is actually leaking air? I took the old hose off, but I don’t see it "dry rotting"anywhere as they stated at the dealership. See the pictures and video below. I purchased the Dorman hose off, but after removing and inspecting the old one, I’m not sure there is anything wrong with it. It was a little dirty but I don’t see any holes. The inside wasn’t even dirty.
I don’t know why they would need to do a cleaning either
I couldn’t figure out how to get this hose off in the picture below. I couldn’t figure out for the life of me how to disconnect it. The ring clamps on each were easy to remove but I just couldn’t figure this one out.
Thanks
It looks like you have two clamps there, a spring clamp which you squeeze the tabs together with a pair of pliers. Wide nose pliers work best, like electricians pliers.
The other clamp looks like a one time use clamp like those on a CV joint. You have to cut it off. Cut the part sticking up off with wire cutters or tin snips.
Then just give the small hose a twist to break it free and pull it off.
When a hose has been clamped on for a long time it can be very difficult to remove. There’s always the option of cutting it off. But usually they can be removed w/out cutting, but you have to be able twist them a little first to break the friction hold. Something like the link below maybe …
https://www.harborfreight.com/3-piece-long-reach-hose-grip-pliers-37909.html
Reminds me of replacing a cartridge in a kitchen faucet. The manufacturer’s instructions say to just grab hold & lift the old one straight out. But you’ve have to be superman to do that. With super-human fingers. The only way it can be done by a normal person is to twist it back and forth a few times to break the friction hold. You need a special-shape tool to do that, which is why I suppose the manufacturer says you should just pull it out. They don’t want to have to supply the $2 tool probably. .
They might have found the leak with an evap/smoke machine
Another way to get the hose off if twisting isn’t working is to gently insert a wide-blade flathead screwdriver between the hose and the nipple it’s connected to. lift up carefully to break the seal, then you can twist.
