JohnOlson

Greetings once again Lexus fans,
Will someone please enlighten me about how to find the intake air temperature sensor, perhaps with a photo?
My mother used to tell her friends that her youngest is blind in one eye and can't see out of the other, so that may explain that, look though I may, I am not finding the simple device, which I presume to be a probe of some sort, and located somewhere between the air filter box and the throttle body.
​​body.
Is that much correct?
According to the code P0100 that I get from the autoparts store code reader I need to replace this device but I'll be danged...!
I'm attaching a pic of what I believe to be looking for. Thanks in advance...

LeX2K

Intake temp is part of the airflow sensor, side of the airbox. Try giving it a clean with MAF safe cleaner.

JohnOlson

Gracias Champion, for your answer above.
​Something else my mama said is that her young'un is not the brightest tool in the coop, which might explain why your reply brings up more questions than it answers. So I just removed the MAF but I found nothing resembling the intake air temperature sensor that I was expecting to find, and what I did remove could hardly be considered dirty, as autoparts go. I will post a pic... is this an intake air temperature sensor? When I peer down the barrel of this device I am mystified by what I am seeing, but when I put on my other pair of reading glasses (2 pairs for very tiny print) there does seem to be something fuzzy down there. Is this what I spray with electrical cleaner? Also, is electrical cleaner appropriate to shoot at that fuzzy sumpin`?
Thanks again for the help.

LeX2K

My apologies that is the vortex type not deigned to be cleaned, I was thinking of a newer engine/EFI system. Anyone here have experience with this type of sensor?

Arsenii

Hello,

Are you sure you have P0100 and not P0110?

P0100 in this case is referred to the malfunction of the MAF sensor as a whole, to the Open or Short in the MAF Sensor to be specific, not just the Temperature sensor, even though it's still enclosed inside of the MAF sensor Housing, below is a picture from the Factory Service Manual. Temperature Sensor has its own separate Pins, and its malfunction should trigger P0110 code and not P0100.



At this point, you don't have much to loose, so unless you see any damage to the wiring, you can try cleaning the sensor carefully, even though I doubt it will yield any results. There is a way to test it by measuring its Output Voltage, but you must be very careful not to cause even more damage, and considering the price of a used MAF sensor, may be easier to get one from the Junkyard for a test and go from there.

I don't think it is actually, it's a regular Hot Wire MAF, just enclosed a bit more than usual, below is a picture of the Karman Vortex Sensor.



Hope this helps and best of luck!

JohnOlson

Greetings Pole,
You are right the AuroZone guy came up with 2 codes for the CEL; P0100 and P0110. The P0100 seems to indicate the cheaper of the two devices so I decided to replace it first, only trouble is I can't find it. Question#6, is it in this thing? If not, where is it? The MAF seems to be clean enough to eat with.

Arsenii

Again, as written before, both P0100 and P0110 are both going to One item - your MAF sensor, both MAF and Temperature Sensor are sitting in one Housing, hence why there are Two wires on the inside of the MAF Unit, refer to the picture in a previous post.

The fact that both came up at the same time makes me wonder if the wiring was actually plugged in when the fault occurred, could be that someone unplugged the MAF Sensor, tripping the code. To find out, connect the sensor back in place, ensuring that the Clip on the pigtail is Latched, clear the codes by Disconnecting the Battery for a few minutes, and see how soon it would come back up, if at all. If you have a Scan Tool capable of showing Engine Live Data, check the MAF sensor Output, it should be 3.5 - 4g/s at idle.

The codes suggest either Open or Short in the Circuit, so unless the cleaning agent can grow damaged Metering Wire back together, there is little chance that cleaning your existing MAF Unit would help, unless what's written above helps, there is a chance you will need to replace the MAF Unit, which shouldn't be too expensive.

Hope this helps and best of luck!

JohnOlson

Once again Pole, you suggested, "you can try cleaning the sensor carefully". But what does that mean, no wire brush no q-tip? What would be careful. I have tried 70% isopropyl alcohol so far. That's it.

LeX2K

You're not supposed to touch the wires you can ruin the sensor, spray with this.

Arsenii

The MAF sensor is very delicate, the wire is precisely calibrated, any disturbance to it will cause it to stop working altogether, or worse, start feeding false information to the ECU, making the engine run poorly without triggering a single code, it can be tricky to diagnose.

There is a cleaner meant specifically for MAF Sensors, here is a link, read the instructions thoroughly and make sure to follow them, do not use the sensor for at least 10 minutes after cleaning, in case if the solution didn't evaporate fully. Any attempt at touching the sensor, let alone physically cleaning it will likely either bend or otherwise damage the wire, or leave a film behind, rendering it unusable, and yes I understand that you know it, just making sure for the future.

With that, I would start with simply plugging it in and seeing if the code will disappear on its own, as it is very unlikely for both sensors to fail at the same exact time, even if they are in the same housing. Other things to try include checking the power between Pins 2 (GND) and 4 (12V) on the Pigtail, then checking the Resistance of the Temperature Sensor inside the MAF, Pins 1 and 2 on the MAF Unit, keep in mind that the pins are Flipped when you are looking at the mating part of the connector (the part that a Pigtail plugs into), Pins 1 and 2 will be the Last ones on the MAF, not the first as shown in the pinout below.



Hope this helps and best of luck!

JohnOlson

Well I bit the bullet and sprung for a new MAF gizmo. I called Autozone first... $87. Then I tried ebay motors... $33. BINGO!
Should be here in a week or less, I'll let you know if if gets me back on the highway.
Meanwhile thanks to you all for the advice.

Arsenii

Welp, I would still try plugging the old one back in..

Yep.....

LeX2K

Aftermarket MAF

JohnOlson

So I installed a new MAF sensor ($33 from ebay) and that seems to have cured the hesitation my '97 es300 was having accelerating off a stop. In fact the ol' gal seems downright spry now.
I don't understand how this device might have caused her to conk out completely and leave us setting on the shoulder of the road to Rocky Point for a half hour, which leads me to wonder if something else is wrong. This is our México car after all.
Well, gracias for all the ayuda!