1st Gen Automatic Transmission Temperature PID for Torque

I use Torque for monitoring several things on my truck including the transmission temp. It requires a custom PID but it works pretty well. I didn't see this info anywhere on TW and it can be a pain to find elsewhere. So, here what you need: (these settings work on my 01, your experience may vary)

In Torque, find the Manage extra PIDs/Sensors menu and open it. This is where all the custom PIDs are stored. Hit the ... In the upper right corner and select Add Custom PID.

Mode and PID: 01B4
Long Name: 1st Gen Tacoma Trans Temp
Short Name: Trans Temp
Min Value: -50
Max Value: 300
Scale Factor: x1
Unit: °F
Formula: A*(9/5)+32
The rest leave as default.




If you prefer Celsius the Formula is just A and change the other values to display however you like.

I'm not an expert on Torque or PIDs but if anyone has questions I'll do my best to answer.

 

Nice. I think you typo'd 38 for 32 in the temp conversion. How do you display the app - in a head unit?

 

ClevSix, where did you get this PID and formula from? Some people seem to have different PID address and the formula is different. I'm not suggesting that yours is wrong, just trying to sort out which version gives the best result. Thanks.

 

He’s got an 01 which could limit the comparability especially to pre-00 or 03-04 trucks. @BartMaster1234 may know. @sykorabj put the @ symbol in front of a person’s handle which gives them a notification (sometimes even our own threads don’t notify when someone comments once in awhile)

 

I think 1999 is the first year transmission temps could be read by a monitoring device. My 1998 is unable to on a Scangauge II.

 

Thanks, fixed it!

 

I got it from a buddy with a 99 4rnr.

As for the different formulas, most of what you find on here works for 2Gen & 3Gen. Some 1Gen 04s use the 2Gen codes (I know of one). I've been told 98 is where you start to find trucks that can pull the trans temp from the OBDII port but not all 98s work. Some time in mid 03 they started to update the transmission and it changed the code. However, some 04s still use the older code.
What I do know 100% is the code I put here works on my truck.

 

Mine is a 2004. I tried your setup this morning and it gives 85F just sitting there not running. Seems reasonable. Will have to monitor later today when i take a drive.

The formula for C to F is normally *(5/9)+32. I figured that -32 was a typo but when I use +32 the non-running temp is 149F, which is not reasonable. I wonder why its -32 instead of +32??? Maybe the min value makes a difference in offset.

 

Good catch. The easiest way for me to remember is that you have 40 and 100 which are basically the same and friendly numbers with mental math.

The 9 and 5 in the formula compensate for the size of the temperature demarkations being that ratio to one another every 5 Celsius degrees to 9 Fahrenheit degrees (which the 100 vs 212 boiling point helps me to remember which ones cover a bigger temperature range per “degree”.

And the 32 has to be added to the Celsius when going to Fahrenheit because “0” in Celsius is “32” in Fahrenheit where it’s the freezing temperature of water. Obvious when sitting down and thinking about it, I know, lol.

 

Actually, that was a typo, LOL. I guess putting a thread together before coffee was a bad idea. I fixed it and added screenshots. Hopefully that was the last typo.

There are several ways to write out the conversion from C to F. Here are a couple of the more common ones.

F=C*(9/5)+32
or
F=C*1.8+32

Not needed for this PID but here's F to C
C=(F-32)*5/9
or
C=(F-32)/1.8

As for me, the temps I see start are whatever the outside temp is and if I let it sit idle for a long time it will be within a few deg of the engine temp. Usually around 190°F. It gets up to about 220°F at times.

 

Since you brought it up, I use every 20 deg C for brain friendly switching between C & F:

C - F
-40 = -40 (both are the same)
-20 ~ 0 (actually -4)
0 = 32 (freezing point)
20 = 68 (room temp)
40 ~ 100 (actually 104)
60 = 140
80 = 176
100 = 212 (boiling point)
160 = 320 (F is double C)

 

This is great!

All the research I had done before is that the 1st gens didn't pull trans temps. Granted that was a few years ago.

@ClevSix, just to confirm, the PID code is (zero)1b4, not the letter O, correct?

I'll give this a try in my '04 are report back.

Thanks!

 

Yes, it is a Zero. It is hexadecimal (0,1,2,3,4,5,6,7,8,9,a,d,c,d,e,f).

 

Interested updates...

I was worried that the PID address wasn't right for my year, so i took a heat gun around the area of trans temp sensor and it definitely affected the reading. That confirms 01b4 (zero not the letter O).

In further troubleshooting, I took out the C to F formula and just read the signal direct. It shows 61F which would be in the right ballpark. Could it be that my ECU is already giving F? Or maybe torque pro already has a conversion factor running?

Ive heard about a temp self check routine for trans fluid change. Something blinks when the trans reaches the operating temp. That might be a good way to check the upper temp reading.

 

It's unlikely that the ecu is reporting in Fahrenheit but not impossible. Form what if heard Toyota made several minor tweaks over the years and strange things show up from time to time. What year is your truck?

 

Nevermind, I looked back and see where you said you have an 04. From what I understand you can find some funny things with the 04s. Maybe the engineers were having a little fun testing things while getting ready to transition to the 2nd Gen?

 

After a 30 minute easy drive across town, the raw value (A) with no formula went from 61 to 111. A change of 50. If I scaled that by 9/5 and adjusted it for outside temp of 63F today, the the formula would be A*(9/5)-47. And the temp at end of drive would be 153F. Does that seem reasonable?

I might go ahead and do the trans fluid change temp checking procedure as a way to confirm.

I also have access to a 2002 tacoma to see how it compares.

 

I just tried to open torque on my phone, which recently updated to Android 11, and it failed to open... It seems the dev's have stopped updating Torque, what other apps have people tried that work well?

 

So I just went out and connected Torque to my 2004. Didn't start it or run it, and it's been sitting all day in the sun (ambient is high 80's/low 90's F)

With the A*(9/5)+32 conversion, the temp read 147 degrees.

I removed it (no conversion) and the temp read 65.

Neither one of those really seem reasonable to me.

For reference, my coolant temp (~86F) and my intake temp (~104F) both seam reasonable, and they are "stock" PIDs so I trust their readings.

@ClevSix you said that it's possible that the 04's might be using the 2nd/3rd gen PID conversion, so out of curiosity, I tried the one I use for my 2017 4Runner's trans temp, and got ~77 degrees. More reasonable than the normal C to F conversion, but I need to drive it around to see what kind of temp swing it has.

Screenshots:

 

I tried out the 2nd gen formula and it works pretty well. I end up with 69F not running and ~160F light driving in town.

A closer look at the math...
(A*256)+B is a way to combine two 8 bit registers in order to get 16 bit performance. I actually watched the raw values for A and B and observed that B changes in increments of 32 up to a max value of 256. That means B has 4 bits of data. A and B combine for 12 bits.

The ending -400/10 means that there is a -40C offset, or that a digital value of zero equates to -40C. The value 256*7/100/10 turns into 1.792, which is the conversion from C to F (ignoring the rounding error)

I think a better way to write it would be 1.8*(A+B/256)-40. Or if 8 bit resolution is okay, then just leave out B and you have 1.8*A-40.

The min/max values turn out to be -40C to 216C. 8 bit resolution is 1C wheras 12 bit resolution is .0625C = .11F. Basically its the difference between having a decimal value or not.

All of this applies to the 2004 model, not the 2001 model.