P3190 Code & Death After Oil Change

If cleaning up the MAF sensor, and briefly brushing the throttle body/butterfly valve with a toothbrush and alcohol, then disconnect the 12v to reset the fuel trims. After reconnecting the 12v, it will take two (2) attempts to 'ready' the vehicle. What is MFC again?

 

Ask the oil change place what else they might have done. Let them know the current state of your car too.

MAF sensor disconnected? Air filter housing lid incorrectly replaced? Air conduit not pushed back on properly or clamp left loose? PCV hose disconnected?

did you ask for just an oil change, or agree to a “look over” as well? Not that that would stop them…

Did you see this thread:

Stranded in sulphur LA with a P3190 after oil change | PriusChat

and yeah: what is MFC?

 

The thing is, the P3190 code tells you only that the engine is producing a small fraction of the torque being asked of it.

That's a symptom description, not a diagnosis. The human just has to check all the things a human would have checked in the olden days when an engine was running poorly and producing a fraction of its output.

 

Debris in the oil filter and you tell them to put it back on? There should be no debris in your oil filter. An oil filter is cheap come on....

You may have really bad mice damage. The AC cabin filter behind the glove box and the engine air cleaner are now a Days Inn for mice. And when there in that free hotel they like to snack and they have probably chewed on many a wire in your car.

Your car lives outside.

Also take the back hatch out and look in the spare tire area there's alot of mice infiltration there too.

This is a very common issue with a G2 Prius and they can do an amazing amount of damage. They can total a G2. This is a very common issue on this site. The wires in a G2 are soy based and mice find them delicious.

Btw, the oil joints use an Alldata car info bible for oil capacity and the G2 info in that book is wrong. It states 5 quarts for a G2 when the car takes 4 so if you throw them the keys and say oil change you get 5 quarts of the worst vat oil ever. So I would bet your engine is very over filled by 1 quart of oil maybe more. That may cause the warning lights you see.

Here's a link to the Search Forums on this site about mice damage. Lost and lots of reading:

https://priuschat.com/search/413853164/?q=mice+damage&t=post&o=relevance

 

It didn't though; that's the thing. There it was, happily running its engine, basing the fuel injection on the MAF reading as it is programmed to do, and suddenly what it was programmed to do, which was working great a moment before, now only produces sucky under-20% power. It doesn't know why. Even if it noticed an abrupt drop in the MAF reading, it has no independent way to know whether the sensor just did that, or a sock just got sucked into the intake and the lower MAF reading is correct. Or the problem could be something else entirely. So it says "hey boss, the engine won't make much power, I'll need your help to figure it out."

There are MAF-sensor-specific codes it can set if the signal from the sensor is recognizably bogus. In that case, you'll get one of those codes. I don't think those codes even do prevent it from starting the engine, by the way; it just says "I know I can't trust the sensor, so I'll just guess on the fuel injection based on throttle position and RPM" and the engine can usually run sort of OK that way.

 

Your finding is the first thing that came to my mind when you described your maintenance visit. One thing you can do is follow up with the maintenance shop and explain to them what you found. They need to know so they're a bit more careful when removing and installing air filters. Your experience is not the first for this exact 3190 scenario.

 

1/4” steel mesh (rodent/bird mesh) over the engine air intake.

Attached is our 3rd gen, but sim I think could be done:

 

TMR might have the simpler, critterless story: somebody checked the air filter, and let a little bit of something drop from the dirty to the clean side.

 

Sometimes I forget and picture the way Gen 3's air box is arranged, where the dirty side is below and the clean side is above, making it harder for a little bit of something to 'drop' in. But then I remember, the Gen 1 and 2 air box was not that way.

 

I'm pretty sure it is that way on a Gen 2 as well as I just did the engine air filter inspection on my Gen 2 yesterday. Unless I'm not understanding precisely what you're meaning.

 

looks like air enters from underside of air filter, flows up.

 

But then it reverses at the cover and goes back down through the air box, which sits right over the throttle body.

So if there's debris on the underside of the filter and you take the filter out and the debris drops into the box, it can end up in the engine or the MAF sensor.

Contrast the Gen 3 air box, where the duct from the box to the throttle body comes from the lid.

For your debris dislodged from the air filter to fall into that duct, it would have to fall up. (It would also have to get through the non-replaceable carbon filter that lives in the lid. )