Monitor Trans Temps: Torque Pro App (Android) & OBD Jumper Method

Starting in 2004 Toyota 4Runners started coming with a sealed transmission (no dipstick) which makes checking / maintaining the proper trans fluid level a bit tricky, especially since to do so you must open the overflow 'check' plug only when the trans fluid temps are between a set temperature range. For example, my 2007 4Runner Factory Service Manual specifies the level must be checked between 115F and 130F for A750E and A750F transmissions. You'll want to be sure to check and make sure what range yours must be in before proceeding.

So, how to monitor the transmission fluid temp?

The easiest but least accurate way would be to use an infrared thermometer pointed at the pan as it warms up. This method is generally frowned upon as many consider it not accurate enough. As such I won't be recommending or discussing it here any further other than I will point you to this point in this YT video in which Faye Hadley (of MotorTrend's All Girls Garage, Motor Mythbusters, etc) uses the Official Toyota Techstream diagnostic monitoring computer application (it's expensive and I likewise won't be covering it here) and compares what the actual temp is to what an IR thermometer shows. In her example the IR gun a few inches from the pan reads a few degrees lower than actual. And here's yet another video, this time by a 'Joe Howto', that goes back and forth between Toyota Techstream monitored actual temps and an IR thermometer on the pan and he likewise runs just below actual. YMMV.

Let's get to the two methods I will go into detail explaining. Personally I prefer to use the App method which I'll explain last, if just because once set up it's much easier to do by yourself, plus it can be used to monitor trans temps while driving which can be useful when towing or whatnot, which the other methods can't. The drawback is it's not free.

1. The cheapest way, for the cost of a small paperclip, is explained in the Toyota Factory Service Manual and involves using a jumper wire or paper clip between terminals 4 and 13 in your 4Runner's OBD port. Before beginning this method the trans oil temp must be cold because this method involves watching dash lights to show you 1) that the Transmission Temp Check Mode has started, then when the low temp of the check range is reached, and then when the max temp has been hit, all as the vehicle idles. This can take 10-15 min on a cool day or happen much more quickly on a warm one.

Here this method is explained in the FSM for my 2007 4Runner. The steps are the same for other Gen 4 (and Gen 5*) years and engine/trans combinations...



Note that, at least in my 4Runner, the OBD port is upside down from the way it is pictured in the manual. Nevertheless, even if I had not noticed that and started counting at the top left 1,2,3,4 and so on I still would have placed the jumper in the same pin locations. I used a small paperclip to jumper mine like so...



After installing the jumper in the proper pin locations start the engine. You'll notice the dash lights will start flashing like crazy. This is normal at this point.



Now shift back and forth between Neutral & Drive every 1.5 seconds for 6 seconds until your 'D' drive indicator or your 'A/T Oil Temp' light on your dash will light up for ~2 secs and goes out to let you you know that the vehicle has entered Toyota's Transmission Temperature Check Mode. Although the 2007 Factory Service Manual (excerpted above) only mentions the 'Drive' indicator it's actually the 'A/T Oil Temp' light that comes on in my 2007 Limited 4Runner.



At this point you pull out the jumper and let the engine idle letting the trans temps to rise until the 'D' or 'A/T Oil Temp' light comes back on steady letting you know that the transmission fluid has reached the minimum temp for a fluid level check. You'll want to be ready beforehand with the tools you'll need and a catch pan underneath so that as soon as that light comes on and stays on you'll have time to complete the fill-level check before the indicator light starts flashing to let you know the temp has now risen out of range too high.

And just for good measure, here's a video from TheCarCareNut explaining the OBD jumper method. So there you go. Between the FSM instructions & pinout, my description of the process and images, and TheCarCareNut's video, you can do this. I will say that this is something you should probably do a practice run first and that it's much easier with two people, one to watch the dash and the other underneath ready and waiting for the signal to let the level check overflow plug drain till it trickles.

2. And that brings me to the easiest method, but it's not free. For this method you will need (a) an ELM327 compliant OBDII bluetooth dongle. These start around $15 and up. The one I'm using is the BAFX Products Android Wireless Bluetooth OBD2 Scanner that set me back about $20. You will also need (b) the Torque Pro app on your android device. This is the 'not-free' version that currently runs $5 on Google Play.

First thing you will want to do is plug in the OBDII dongle, turn your key to the on position, and then in your android device go to the bluetooth settings to pair the new device. You may need to look at your OBDII dongle's instructions to see under what name the device will appear to pair to it.

Now first open the Torque Pro app and setup your vehicle profile if you haven't already done so. Then, from the main screen, click the gear icon (menu button) > Settings > "Manage extra PIDs/Sensors". On the next page click the menu button > "Add custom PID" > "OK"



NOTE: This custom PID data is for 4th gen 4Runners (2004-2009). For Gen 5 keep on scrolling as I've also added that data set towards the end of this post

At the top for "OBD2 Mode and PID" enter "21d9"
For the 'long name' and 'short name' options you can put whatever you want.
For "minimum value" leave it at "0"
For "maximum value" put "300"
For "scale factor" leave it as "x1"
For "unit type" type in "F"
Under "equation" type EXACTLY: (((((G*256)+H)*(7/100))-400)/10)​

*Note that there are FIVE beginning parenthesis at the start of that formula and no empty spaces. Once you have finished typing it in correctly there should now be a green check next to it.
You can skip the rest and click "OK"



Now that we have created the new custom PID, we just need to add the new gauge to the Torque display.
From the main screen select 'Realtime Information'.
On the next page click the gear/menu icon > 'Add display' > I chose 'Digital display' here. You may prefer a different look. > Select the new sensor under whatever name you chose for it (I chose 'Trans Temp') > Select a a size for your widget (I chose small), and now it will let you place the new gauge wherever you want it.




*NOTE: I've verified this custom PID formula works for my 2007 and as I understand it should likewise work for other Gen 4 4Runners 2004-2009. For Gen 5 4Runners starting in 2010, I believe the data for the custom PID should be as follows:

OBD2 Mode and PID: 2182
Long Name: whatever you want
Short Name: whatever you want
Min Value: 0
Max Value: 300
Scale factor: 1
Unit type: F
Equation: ((((A*256)+B)*(7/100)-400)/10)
​

Lastly, there are other OBDII Apps that also work with any ELM327 compliant OBDII bluetooth dongle that also can monitor Toyota trans temps, like 'OBD Fusion' is one I have heard about. As I understand it, to get it to work you must 1) purchase the app itself ($5) and then 2) once set up for your model you must purchase the model specific enhanced diagnostics features (~$10?) which include the trans temps monitoring. So, if you'd rather spend just a few more coin for a method that some may find easier than entering the custom data PID equation on their smartphone, this may be the route you want to go.

Cheers. Happy 4Running.

 

Greetings and thanks a LOT for your efforts,, I have a 2005 Lexus gx470. I want to monitor the transmission temperature while towing. I've purchased and returned several devices that I was assured would do this. AARGH!! After reading this, I purchased the BAFX obd2 scanner, downloaded the torque pro app and am now setting it up. I get a warning that if I don't know what I'm doing,, to stop. What I'm wondering is if the PID and codes in your article will work for my vehicle. Thanks, I really appreciate it. If not, do you know where I can find them?

 

I tried like 10 of these dongles and none of them worked and was about to give up and I thought I'd try the bafx one just for s**** and giggles and voila success.
Thanks for the write-up

 

OP, your Torque app instructions were posted here in 2014:

 

@4-Funner I entered the Custom PID as per your instructions & have no temp reading on the TorquePro app. 2007 4Runner, V6. All else seems normal with the app. Any suggestions?