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View Full Version : Troublesome MAF Sensor Circuit Low code


woodamsc
09-11-2024, 09:23 AM
2008 Yaris Sedan, ~190k miles

Bought it at 180k, was running fine for a bit then I started getting cylinder 4 misfire code, and then next day MAF sensor code.

Main symptom was warm starts caused rough idle, driving would usually resolve the rough running.

I just decided to start changing stuff that was likely overdue anyway rather than diagnose :biggrin:
Most of the stuff I changed truly did need changing


I changed Sparks + Coils => car drove MUCH better, but codes remained
Cleaned MAF Sensor with MAF cleaner. It was absolutely covered in crud. => car drove even better, absolutely mint. Couple days later cylinder 4 misfire. Couple days after that, MAF sensor code returned
Cleaned PCV Valve with MAF Cleaner. It was totally gummed up. => Car runs better. Cylinder 4 misfire code has NOT returned, MAF Sensor Circuit Low HAS returned.
If I unplug MAF Sensor while car is running in park, car immediately dies.


Should I just cough up $90 for a new MAF sensor? I can't help but feel the sensor is OK sense the car dies when I unplug it. Maybe a grounding issue?

Currently car runs and drives, but I feel like it's in a limp-mode of sorts. It isn't running ROUGH, but it doesn't feel full power.
Car starts rough, like a there's a slight hesitation, and then it rocks around a bit before it sorts itself out.

Since cleaning the MAF + PCV I've driven maybe 200 miles. I was thinking ECM needed time to adjust the fuel trims or something.

If it's not a bad MAF, what would be left to check? A clogged fuel injector?
At this point I need to diagnose rather than keep throwing parts at it haha

WeeYari
09-11-2024, 11:06 AM
Is the o-ring gasket on MAF intact and providing a tight seal?

woodamsc
09-12-2024, 01:42 PM
I believe so, but ill check for certain when i return home, and look for any other leaks. I changed the air filter recently as well

woodamsc
09-15-2024, 09:28 PM
Yeah everything looks good. I didn't see any cracks on the intake hose either.

woodamsc
10-13-2024, 09:56 PM
New MAF Sensor solved this