MAF sensor resistance test

No major problems, but in case there's a minor problem I tested the resistance of several parts, and they all tested as lower resistance than spec. On the MAF sensor terminals 2 and 3 I got nada. I also tested 3 and 4 in case I had it flipped. A few years ago I had corrosion on some terminals and had to scrub it with electronics cleaner. Otherwise last I knew it gave live airflow data in spec, but that was a year ago.

It's the original part 2225020020 . Used on lots of Toyotas up to 99. Does anyone have this one and can test to see what you get? 5 pins as shown.

 

If you want to upgrade from the torpedo style MAF, you should consider swapping to the newer style MAF (

$158 22204-21010 Internal Air Flow Meter

22204-21010) you'll just need to repin the plug.

 

Assuming your ohmmeter is accurate, getting zero continuity between THA and E2 is a good sign that it's faulty. Can you do the next test mentioned in the FSM? I would do it just to verify that it's faulty. If it fails, definitely replace it. It's a crucial part to the engine's efficiency.

 

Should I have the battery connected while doing the operation test?

I have the multimeter set to 20V, negative lead on its COM port, positive lead on its VOmA port, and with the MAF connector disconnected and battery disconnected I probed terminals 4 (positive) and 1 (negative) on the MAF and got nothing.

To do it with the MAF connector on, I think I need to remove those wires from the connector somehow?

 

Does that fit into the existing MAF housing?

Any tutorial on repinning the plug? I've never done electrical work like that.

Here's what my setup looks like.

 

Not sure why all the nonsense testing, just plug a scanner in and see what it's reading.

IAT and ECT should be within 5-10 degrees of ambient after the truck sits over night.

MAF in Grams per Second (g/s) should be about equal to engine displacement in liters at hot idle, accuracy at high RPM can be checked by doing a VE test.
https://otctools.com/ve

If it's not reading correctly then do some electrical checks.

The resistance check they are having you do is just checking the Intake Air Temp Sensor in the MAF sensor.

 

See the last 4 pages for repinning for the new MAF. You’ll need a new intake tube that accepts the new sensor, but that opens your options to aftermarket intake systems.

https://cdn.shopify.com/s/files/1/0528/2352/3494/files/MAF_install_guide.pdf?v=1624314121

 

The scanner readings are all normal. I guess I'll leave it alone. I've noticed the FSM almost never tells you to use a scanner to check things, when it's often the easiest way.

 

Yea I have no use for most flow charts except sometimes as a guide for what to look for, most are written for robots not true diagnosticians.
They will often have you taking half the vehicle apart ohm checking wires (which is not a good test to prove out a circuit anyway) for something I can test in a few min with a simple unplug it/bypass test/test light.
Often times the tests that logically should be done first are buried 10 steps down in the flow chart instead of being step one.

If I have a good wiring diagram, code set criteria/description & operation give me a good scan tool, a couple test lights of different amperages, and a decent meter I can solve tons of issues as any decent diag tech should be able to.

It's beyond me why manufacturers continue to write flow charts like they do but pay peanuts for diag, that's why alot of dealer techs just fire parts instead of doing any in depth diagnostics.

I guess alot of it is because of the lack of skilled diag techs that they write something that anyone can follow.