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Code P0101 - Low Voltage @ MAF Sensor

42K views 9 replies 6 participants last post by  JCaux  
#1 ·
Here's the rundown: 2008 Mazda 3s manual hatchback:

It started with stumbling/stuttering issues at around 2000-2500rpm while cruising, light throttle, maintaining speed with traffic flow. No codes thrown. Looking around the forums, it seemed like cleaning the MAF sensor was the consensus, so I tried that. Cleaned it with MAF Sensor Cleaner, let it dry, reinstalled it, and OH-MY-GOD-IT'S-SO-MUCH-WORSE. The mild stutter or stumble became a full-on bog, cough, die-at-idle, hell-to-keep-running kind of issue, and immediately threw the P0102 low voltage code.

I replaced the MAF sensor with an aftermarket parts store unit, but that didn't do the trick. My wife was out of town at the time, so using her car as my baseline and guinea pig wasn't an option.

Fast forward to this morning, when I finally had access to both cars and time to play. I pulled the original OEM sensor from my wife's car, plugged my original unit into hers, and drove it for about 30 minutes. No issues at all. No stumbling, no codes, no problems. That's good. That indicates that the original unit wasn't faulty in the first place.

Now the acid test: I put her known-good OEM unit into my problem-prone car, and went out to drive the same loop. I had to abort pretty quickly and head back to the house, because the stuttering and bogging came on just as soon as the engine warmed up, and the car died several times when I had to stop for red lights.

The P0102 code came back, of course, just as it has done every time since I cleaned the original sensor last weekend.

No other codes have popped up.

This leads me to believe that I have a faulty wire in the MAF sensor's harness. Has anyone else had similar experiences and found the solution to be something else, something I haven't considered?

I'm not really in a position right now to just throw money and new parts at the car, and I'm pretty terrible at troubleshooting electrical stuff (it either works, or it doesn't, in my book. :) ), and if I ever owned a voltmeter, I have no idea where it might be now, or how to properly use it if I could find it. It doesn't help that I really don't have a place where I can properly work on the car for any kind of extended time frame.

Just trying to get ideas and verify if I'm on the right track or not before I try to get it to a shop and let them have a go.

Thanks in advance for any advice and help.
 
Discussion starter · #2 ·
Dang it - I meant P0102, not 0101. Sorry about that. :(
 
Discussion starter · #3 ·
Went to a junkyard and found a 2nd-gen 3 with the same MAF sensor connector, and the 2g 3 has about 10" of extra play in the wiring harness for that sensor, so I clipped that out and they charged me nothing for it. Wires were different colors, but I used the old sensor to make sure I was splicing the right wires together. Been four days now, and no codes, no sputtering or dying. Seems to have fixed the issue for the most part.

There *is* a weird kind of flat spot under wide-open throttle, between around 4000-5000rpm, where it feels like the engine just isn't getting enough air. I say it's weird, because if you're cruising around at 3000rpm or so, and roll into full throttle from there, you get that flat spot in the acceleration. However, if you launch it and go full throttle from the jump, it seems fine. I'm going to keep playing with it to see if I can figure out what's what, 'cause I want my 3 back the way it was, and something's not quite right.