ScanGauge... clear up the trans temp myth.

Some of the earlier trucks do not provide the information to the assembly line diagnostic link ( OBD2) Better known as on board diagnostics
This is where the scan gauge and Ultra gauge get their information from
Inside your A340 series automatic transmission , All of you guys have a temp sensor but some temp sensors do not communicate with the OBD2 connection under your dash .
Some guys make the mistake of purchasing a scan gauge or ultra gauge and then find out they cant read the transmission temp sensor data .
Some guys think they found the transmission temp sensor and turns out its the engine temp rather than the transmission temp . Dont get fooled .
I still highly suggest using a digital gauge though . So much information is available to you .
Dont wait for the transmission temp light to pop up . Toyota illuminates that light far too late at almost 300 degrees .
At 300 degrees , you have literally cooked your transmission fluid which depletes all the additives in the fluid
For those of you who cant read the transmission temp data , Go with an analog transmission temp gauge .
Got a thread started here that shows you what to purchase if you cant get live temps from the OBD2 connector

https://www.tacomaworld.com/threads...l-toyotas-write-up-with-many-pictures.526283/

 

Ok. Thanks for the info I had bought the scan gauge to adjust for speed and mileage since I'm running fj cruiser wheels and bigger tires my speedo was like 9% off. I don't plan on towing with the truck but I was just gonna run a aft temp gauge on my scangauge if possible I just didn't know if my truck was equipped with the sensor and I was doing something wrong with the scangauge or what the matter was. Thanks again

 

Double checked the codes I had them correct ig my truck just doesn't communicate trans temp to obdII

 

Sorry to hear that. I guess using the a manual temp gauge is the only option.

 

From what I discovered a few years ago, 1999 was a transition year. Some trucks have the wiring for the sensor to communicate with OBDII, some don't. My 1999 TRD Prerunner 3RZ AUTO Extended Cab does not.
@CS_AR, what are the full specs on your truck?

 

1999 Pre-runner 5VZ TRD OR Package Ex cab.

 

Ok thanks for all of your help guys at least I know I was doing something wrong

 

So the difference between our trucks is 5VZ vs 3RZ.

 

Are the auto transmissions the same between 5VZ or 3RZ? I can get my MFR date if it will help.

 

They are the same transmissions, but there are many slight variations. @gearcruncher can attest to that.
They obviously have different bell housings, and maybe different kickdown cable connections.

 

Go to the ATSG website and plunk in your info https://www.atsg.us/atsg/transtype

I believe you have to look at a factory wiring diagram to figure out why some members cant get the transmission temp data and some can

The temp sensor inside the transmission communicates with the ECM but that part of the ECM does not communicate with the OBD2 port

This question comes up a lot at Tacoma World so you would be a Tacoma World hero if you figured it out .
The answer would certainly be worth the ever so coveted Tacoma World Trophy Point .
To this day , nobody has earned a trophy point hehe


You guys can do all the research you need at this thread .
https://www.tacomaworld.com/threads...sions-write-up-your-4-speed-automatic.325531/

 

01 Prerunner with 5VZ and A340E and I’m monitoring trans temps. The trans temp readings behave like I’d expect when I’m driving around so I doubt I’m confusing it with engine temp. My best example is when I hit overdrive I can see the trans temps drop right away, yet water temp remains unchanged. I attribute this mostly to the inline trans fluid cooler I mounted behind my grill, airflow, etc. This pic was right after startup so that’s why everything is so cold.

 

Whats the difference between the a340 and a340e

 

I am pretty sure the "e" version came on prerunners (no t-case). Mine is an a340f. Its a v6 4x4.

 

Oh ok thanks

 

Sub'd

 

Just used this on my "Scangauge II Ultra" for the 2003 Taco.

 

Reviving an old thread. Does the ScangaugeII read transmission temps for a 97 tacoma? If I remember correctly when I used an obdII scanner it read it, but havent seen anyone report it. Thanks!

 

I'm pretty sure it does not. The ECM does not put that info into the data stream going to the OBDII port. For sure it doesn't work on 95.5-96 models.

 

thanks, I guess ima just make sure the idiot light doesnt come on