[ptheguru22]

Hey y'all, my 98 sonoma (262ci v6 SLE trim) keeps throwing the "MAF circuit low" code but I've tried three different MAF and nothing's changed. If anything, it got worse on both of the two new MAF units and I'm honestly at a loss for what to do next. Air filter's clean, airflow to the intake is clear, the exhaust seems fine, so I really don't know what to check next.

 

[Gen210]

What is the code that is showing on the scanner?

 

[needawheel]

did you clear the codes?
pretty sure thats what mine said when i unplugged my maf and drove it a few times...
one or two times i cleared the code and plugged the maf back in and the code would come back despite the maf being plugged in... there was something odd going on with it and i never figured it out. a battery disconnect ultimately fixed my random maf code. i didnt replace my maf and it hasnt thrown a code since...

yours might also be the wiring to the maf...
what brands of maf are you using?

with mine there was definitely something odd where the computer had almost decided it could run better without the maf input and was electing to ignore it despite it being plugged in...
fwiw, mine needed new spark plugs during that time and was misfiring.

ps. mine probably had vacuum leaks at that time too... you should get your hands on all your vac hoses and pcv to make sure they havent crumbled... smoke test it too.

 

[ptheguru22]

Hmm. The code I'm getting is P0102 and sometimes P0446 (evap system code). I've tried clearing it out several times, and I gave each MAF I've installed over 100 miles of drive time to break in. I used the stock MAF, an AC Delco MAF from rockauto, and a Blue Streak Electronics MAF from O'reilly.

 

[ptheguru22]

I do have a very weak battery as well. The stock MAF's signal wire was putting out 5.6-5.8 volts when the vehicle was off with no key in the ignition, so I'm positive the stock MAF is bad, probably some sort of short.

 

[ptheguru22]

The P0446 didn't start showing up until after I replaced the MAF the first time. P0102 has been consistent with both new MAFs and the stock MAF was throwing P0104.

What is the code that is showing on the scanner?

 

[needawheel]

i would rectify the battery issue first. also clear the 'keep alive memory' by disconnecting the battery first then touching the + and - wire leads together to drain the capacitors and memory. its easier said than done with the side mount leads...

those are cheap and easy things to rule out. you will have to rectify the battery sooner or later, might as well rule it out now.
my next guess would be the maf wiring maybe having an issue, but considering my experience with my truck refusing to forget codes caused by unplugged mafs even after i plugged it in and cleared codes, i would definitely try wiping the memory with the battery disconnect. you dont want to maintain 'keep alive memory' from removed maf's anyways...

 

[Rhotpursuit]

Aside from the first mention of vacuum lines, I've seen nothing else mentioned. After all..it is a mass AIRFLOW sensor.

 

[oldeerslayer]

Sounds like you have a vacuum leak. If air is getting in between the MAF and the intake valves at some place like an air horn seal, throttle body gasket, a leaking vacuum hose, or leaking intake manifold gasket, the engine will use that air for combustion, resulting in less being sucked thru the MAF. Which will cause a P0102. S10's are famous for leaking vacuum hoses in the group of hoses next to the ABS module. Cracks due to dry rot or disconnected hose(s) is common. The hose from the intake is 7/32 and the rest are 5/32 in size.
Also check the hose to the brake booster, PCV valve, and the breather tube from the pass valve cover to the intake air horn.

 

[ptheguru22]

Sounds like you have a vacuum leak. If air is getting in between the MAF and the intake valves at some place like an air horn seal, throttle body gasket, a leaking vacuum hose, or leaking intake manifold gasket, the engine will use that air for combustion, resulting in less being sucked thru the MAF. Which will cause a P0102. S10's are famous for leaking vacuum hoses in the group of hoses next to the ABS module. Cracks due to dry rot or disconnected hose(s) is common. The hose from the intake is 7/32 and the rest are 5/32 in size.
Also check the hose to the brake booster, PCV valve, and the breather tube from the pass valve cover to the intake air horn.

Actually, that makes a TON of sense, I'll be sure to check that out. Thanks

 

[Gen210]

Be sure to disconnect the battery for atleast 15 minutes

 

[ptheguru22]

Be sure to disconnect the battery for atleast 15 minutes

Ok, will do

 

[Original_Owner_86]

Hey y'all, my 98 sonoma (262ci v6 SLE trim) keeps throwing the "MAF circuit low" code but I've tried three different MAF and nothing's changed. If anything, it got worse on both of the two new MAF units and I'm honestly at a loss for what to do next. Air filter's clean, airflow to the intake is clear, the exhaust seems fine, so I really don't know what to check next.

-Check the PCV valve.
If not that:
-Check every single vacuum line carefully. Flex them at connections to check for splits.

 

[ptheguru22]

-Check the PCV valve.
If not that:
-Check every single vacuum line carefully. Flex them at connections to check for splits.

So it looks like it's the PCV valve hose, the elbow connection isn't stock or a compatible replacement, rather it's just a small strip of too large vacuum hose.