Toyota Prius Problems

Stalling or Loss of Power Due to Debris in Mass Air Flow Sensor on Toyota Prius

Problem Description and Possible Solution

A no start or loss of power issue may develop if debris falls into the mass air flow sensor when changing or inspecting the air filter. Care should be taken when changing of replacing the air filter in order to avoid this issue.

(28 people reported this problem)

Toyota Prius Vehicles With This Problem

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Average mileage: 75,383 (28,000–185,000)
11 model years affected: 2001, 2002, 2003, 2004, more2005, 2006, 2007, 2008, 2009, 2010, 2012
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Viewing 1-8 of 8 comments
Car conked out while driving. Lost power then shut itself off. Check engine light came on along with BIG RED exclamation point! Mechanic diagnosed, not sure how he came to the mass air flow meter, but that's what they are doing now. I had checked the air filter yesterday...was not aware of any debris that could have fallen down there, but am horrified to think I caused the problem!
Car stalls and all warning lights come on. Diagnostic show code P0101 MAF. Hose was tightened but happened a month later.
1st time: Started the car after a heavy rain. About one minute later the car shuddered, lost power. The "red triangle of death" appeared on the display, and battery displayed zero charge. The car slowed to under 10 mph. Pulled into a parking lot where the car died completely. It locked up so that the car could not be pushed. After about 5-10 minutes the car started up and seemed to run ok, but the red triangle remained on the display. Drove about 10 miles & parked the car overnight. The next day the car worked fine, with no display warnings. Subsequently drove short trips over 3 days w/ no problem.

2nd time : Hot dry day. Drove the car about 15 miles, parked for 30 minutes, started the car and drove about 2 blocks. Car lost power. There was no shoulder or driveway to pull into. About 30 seconds later the car died in the middle of the street. After 1-2 minutes I was able to start the car & drive slowly into a parking lot where it died again. Display again showed zero battery. After about 5-10 minutes the car started up and seemed to run ok, but the red triangle remained on the display. Drove about 15 miles, with battery recharging to near full. Parked the car overnight. The next day the car worked fine, with no display warnings. I took the car to Toyota dealer who kept the car overnight and attempted unsuccessfully to duplicate the problem. Diagnostics showed consequential data that the engine stopped, but no primary cause for why the engine failed. Dealer said two or three possible causes, but unable to pinpoint the problem. Advised me that the next time it dies to have the car towed to the dealership. I no longer feel safe to drive the car more than three miles or to drive on any highway.
I did a routine inspection of my car's engine compartment, and replaced the engine air filter and cabin air filter. The next time I drove the car the gas engine started to loose power and the red triangle warning light came on, along with the check engine light and exclamation light. However, I was still able to drive the car on the electric motor at a slow speed (under 24 mph) I quickly found a safe place where I could park the car and it could be towed to the repair shop. My mechanic researched the error code on the internet and said the problem was most likely my mass air sensor. He cleaned the sensor, which thankfully was an inexpensive repair, and the car ran fine. I did not think that my opening the air filter earlier may have caused the problem. However, some days later I did my typical engine compartment inspection (I live in the rurals and mice get into the engine compartment and air intake) and opened the air filter box above the mass air sensor. After I did this and drove the car, the gas engine immediately loss power, the various dash warning lights came on, and the engine eventually cut off, although the hybrid engine was still working. I returned home (200 yards) where I turned the engine on and off, moved the accelerator up and down and tried to see if the engine would correct itself. Thankfully eventually it did and all the warning lights slowly went off. The car has been running fine ever since. I now feel fairly certain that my opening the air filter box and removing the air filter caused the problems with the mass air sensor and the engine failure. NOW I WILL ONLY OPEN THE AIR FILTER BOX TO CHANGE THE FILTER, AND WILL DO SO VERY CAREFULLY SO AS NOT TO PLUG OR IMPAIR THE MASS AIR SENSOR. And if the car acts up after such a change, I will know the problem.
car stalled suddenly, diagnosis at repair shop was that a bug was in the mass air flow sensor.