P0101 and P0127 codes showing

According to those codes, you should've noticed a sizeable mpg decrease over the past few fill-ups. Check for leaks between the MAF sensor and your intake manifold gaskets. Any leaks along that pathway would/should throw those codes - unless you actually have a bad MAF. A bad MAF sensor would lead to either a lean or rich burn, depending on which way the MAF is failing. I would probably drop a new MAF into it before trying the dealership; If it's going to less than the diagnostic fee. The dealership jockeys would probably do the same to rule out that sensor failure. Most of those kids likes to use their brains to surf the web instead.
A quick way to check for leaks is to fire up the engine and use propane gas torch. Don't light the torch, just turn it on and run the gas over the suspected leak areas. Engine idle should increase, if there's a leak there. That's also a quick easy way to find vacuum leaks.
A failing O2 sensor can also cause a rich mixture, but you'll need a better scan tool to diagnose that.

Good Luck....

 

Yeah I keep a bunch of these kind of things marked in a drawer so I can do swaps like that to see because then some of this stuff it's hard to even tell in the freeze frame dating It's quicker to change the part than it is to sit there with the tablet in hand looking at rows and rows and rows of numbers and percentages I can stick an MAF on generally before the tablet boots or close to it

 

I've got a Mitsubishi lancer that's in here right now with a sketchy fill up at a known not good place to fill up and all of that and it's bogging down and running poorly and everything on the car looks pristine and well taken care of even though the car is 23 years old or so and it runs great until you floor it and of course this is a full gas car not a hybrid so no point here but so yeah bad fill ups are real thing

 

Check the electrical connector to make sure it is fully engaged. Disconnect the connector, then use electrical contact cleaner. Let the connector dry and put it back together again.

 

mendel, why does google show P0127 as 'intake air temp sensor'. is that part of the maf?

 

Good catch—I just assumed Mendel had looked up the codes, didn't double-check.

P0101 is an interesting code. The ECM computes two estimates of the load on the engine—one based on the MAF reading, one based on "driving conditions"—then sets the code if the estimates are not close enough to each other.



P0127 is puzzling because the 2010 repair manual copy I'm looking in doesn't list it as a code the car can set. Being a P0 code, it has to mean the same thing in any car that can set it, so according to a list of the standard P0 codes, "Intake Air Temperature Too High" would be the ticket.



The intake air temperature sensor does happen to be combined with the MAF sensor (it's the obvious blobby thing you see when you look at the MAF sensor, whereas the actual MAF sensing elements are tiny wires deeply buried inside it).

 

Stay away from the Stealership because you're more educated on Prius than the dummy they'll put in charge of ripping you off...

Does your car get parked in a garage? Or outside?

Based on the insane rainy weather / flooding we've been having I bet you got water in all the wrong places and need a really long drive to sunnier places with lots of tanks of gas to dry everything out.

In the meantime, reset your systems with a 12v disconnect and maybe order the cheapest MAF sensor you can find online as a back up plan.

 

Dirty MAF can cause wierd high idle. I was using a contact cleaner from hardware store but after that the car occasionally runs rough. I was thinking, what could it be. I check the spray, it turns out it has some kind of lubricant added to it. So, I use non clorinated, no acetone brake cleaner to wash it off. Since then, it runs smoothly again.
Ensure that the car is off for at least 20 minutes so the wire in the MAF is not hot. Sudden cooling can destroy the sensor.

 

You should use the correct cleaner for it. Then you won't damage it....

 

yes, there are CRC MAF cleaner and other spray available in US but not that easy in Europe to find it