Seeking Voltage Specs for 2014 MAF sensor signal/sensor wires

Hello,

New Tacoma owner here w/ a used 2014 TRD Sport that has been giving me check engine and "trac off" light indicators on dashboard.
The OBDII scan reveals P0101 code for Mass Air Flow Sensor-Circuit/Range performance.
Rather than throwing "parts" at this, or simply replacing the MAF for $100, I did clean sensor w/ CRC MAF Cleaner, noting light immediately went off, only to return a week later during mid-range acceleration around 45 mph. I cleaned again, and cleared code w/ OBDII, noting it returned within a few days. Reset again by disconnected neg battery cable, clearing it again, only to return. Moved on to testing the current one for functioning by checking ground resistance/ohms and the sensor signal wires for voltage when idle and when increasing RPMs in park.

By disconnecting the wire harness from the MAF sensor and using a voltmeter, I've identified:

1. the 12V wire at harness position 5 (far right blue wire) reading at 12.1 V with key in "accessory" mode and engine not running.
2. The 2 ground wires at harness position 1, and 4 (black, red/white), with continuity checked and good/audible beep.
3. The remaining sensor signal and sensor ground wires at harness positions: 2 and 3 (full red, red/yellow)

3a. Inserting a copper back testing wire into back of the plugged in harness with position 2 wire reading 2.42 V at idle. This doesn't increase or change upon increasing RPMs or revving engine in park. Suspect this is the sensor ground wire.

3b. Same back testing w/ wire into back of plugged in harness for position 3 wire notes 1.25 V at idle, and a steady increase up to 2.5 V, while increasing RPMs and revving engine in park. This returns to 1.25 baseline after letting off gas. Suspect this is the sensor signal wire.

I am having difficulty finding the actual Toyota specifications for the 2 sensor signal wires to confirm they are in range at idle and with increased RPMs.

Wondering if anyone in this community might have them, or post a link to them? Thank you kindly for any help.

 

P0101 is a "rationality" code meaning the output of the sensor is outside of the expected range for the given engine RPM and Throttle Position.

MAF sensor accuracy is best checked with a scan tool at idle and calculating VE at WOT.

At hot idle MAF in Grams per Second (g/S) should be very close to engine displacement in liters (4.0 g/S for a 4.0L engine).

VE is checked by doing a WOT pull through 1st gear while recording Peak MAF, Peak RPM, and IAT then entering them into a VE calculator like the one linked below.

https://otctools.com/ve

Also do you have a stock air intake system? Aftermarket air intakes can screw with the MAF sensor readings because MAF sensors are calibrated to the airflow characteristics of the stock intake, changing the diameter of the MAF housing and/or angle of the air hitting the sensor alters it's reading.

 

Freeze frame data would be nice.
But @Dm93 summed it up nicely.

 

Thank you both for responding, and @Dm93 for the resources and troubleshooting. I do need to research a bit more to learn the terms VE, and WOT.
Do you have a preferred scan tool that isn't too expensive? Guess I could swap out the sensor and discern if I have a bad sensor, vs something else causing it if the error continues with the new sensor installed. Could also take to my mechanic, but at $105/hr for diagnostic services, I thought I'd try to troubleshoot a bit myself, even if buying a new tool/scanner wasn't too expensive.

To answer your question, I have a stock air filter box and the air filter is brand new/recently replaced at dealer. Considered, but unsure a cleaner/new air filter would improve the airflow over the MAF sensor so much that I would need time to re-calibrate after being change in the event the prior filter went a long time w/o being changed, and became so dirty and clogged that it didn't let a lot of air through. Perhaps a stretch.

Also wondering if it could be from running 85 octane (R+M/ 2 method), though plenty of people in this forum note having no issues over the years running 85 at altitude (5,000 ft in Denver), despite Toyota recommended 87 octane (sea level). Any thoughts on that or adding octane booster on this tank and refilling w/ 87?

 

85 Octane should not cause that issue.

FWIW, If you want to follow Toyotas flow chart.
It basically says, Check for vacuum leaks. If no leaks found, replace MAF sensor.

That isn't the best way to diagnose this issue. Dm93 post the correct way to check it.
One may look at Freeze Frame date just to be sure the the MAF isn't dropping out completely, or there is some other details to make us suspect a different issue.

Anyways, If you have no scan tool. And you don't want pay a mechanic to diagnose it.
You can throw a MAF sensor at it. I don't normally recommend throwing parts at it.
But with what you've told us, I feel like there's better than a 50% chance a MAF will fix it.

 

All but 1 of my scan tools are in the pro level ($900+), for basic testing like this you really just need one that can do live data and decent graphing which should be easily had for well under $100.
I did a thread on what to look for in a scan tool, that can be found at the link below.
https://www.tacomaworld.com/threads/scan-tool-discussion-recommendations.834898/

Toyota really doesn't give any specific testing for P0101, essentially it says if no other codes or vacuum leaks are present replace the MAF sensor. You would typically get a P0100, P0102, or P0103 if you had a complete dropout/failure of the MAF sensor.

That shouldn't affect it's calibration.

Octane only affects the fuel's ability to resist pre-ignition (detonation), the knock sensor would pick this up and the PCM would retard ignition timing which while it may reduce performance wouldn't affect the MAF sensor.