We’re working on this over on tacomaworld forums as well.
http://www.tacomaworld.com/forum/performance-tuning/183560-write-up-torque-app-obd2-reader-8.html

After a quick re-read of the thread here http://torque-bhp.com/forums/?wpforumaction=viewtopic&t=352.0 on the conversion process, we’ve updated the equation to:

((A*256)+B)*10*(7/100)-400

But it still seems to be notably high (I doubt my transmission is 5000 degrees F)

I’ll update this thread if I learn anything new

Quote from Krookz on January 5, 2012
This is ruggedT on TW

Heheheh. Let’s hope someone on this board knows more than we do!

I’ll test this with the following custom PID info:

21d9
TFT
0.0
300.0
x1
F
((((A*256)+B)*.7) / 100) – 400

Will post what the result is soon.

Rob

Awesome! Thanks alot. Ill check this on mine later

Yea. The FSM states it should be -40°C to 215°C (-40 to 419F)

1) There are two temperature sensors in the 09 AT, “A” and “B”. They read the oil temperature, as one would expect
2) The sensors present the temp as an electrical resistance to the ECU, varying from 79? to 156k? and the ECU converts it to a temp value in °C
3) The Toyota Techstream tool reads the temps from the ECU through the OBD interface, so it must possible for us to do so, too!
4) The ECM speaks ISO 15765-4 (and possibly SAE J1987, they’re both mentioned in the manual)
5) The “B” sensor is placed directly before the oil cooler inlet pipeline, not mentioned where the “A” sensor is
6) The ECU considers the valid temperature ranges to be -40°C to 215°C (-40 to 419F)

I just tried this over lunch, too, and got similar results. Negative values for a while, then some rather small positive numbers after warm up.

I noticed you took out the *10 modifier, I might try putting that back and seeing if it makes more sense. Seems like we’re getting closer!

Quote from LGE RAW on January 6, 2012
Is the response returned in ohms or degrees?

That’s the oddball part – the hex values returned in the response (using the Test feature in Torque) don’t seem to be either, but then again we can’t tell what they really mean. If we interpret them as IEE754 floating point values, we get like 117 for the 0: value. They’re insanely high if read as integers, so I’m thinking they are floats, but we don’t know the scaling for sure. Automotive controller programmers seem to have their own standards for things that don’t always jive with other types of automation software or even general personal computer standards. One of the fellows on TacomaWorld and I have been trying to figure out what ISO spec is being spoken so we can try to track down what scheme floats use in that world, but with no real success so far.

Quote from admin on January 6, 2012
(the test result quoted above was all 0’s which likely means you need the engine running before you get readings from the transmission)

It would then be reasonably trivial to see where the issue is with that gem of information

Interesting… so here’s what I’m understanding:

Eq result: -400 (means the A and B were 0 to get that result)
Response: 00A (I assume is just an OK message)
0: 61d912000000
1: 51E053C000000

So the two pieces of hex data are not A and B? Or are A and B just some portion of the lower bits of those values? I guess I’m just really quite confused as to where A and B come from

A and B are the values immediately after the 61d9 part of the reply – ie the 0000 (which would be A=0x00, B=0x00, C=0x00 and so on…)

or in your latest example:

0: 61d912000000

which A=0x12(hex) and B = 0x00

where A would be 18 in decimal and B would be 0

which in the equation would be: ((A*256)+B) = 4608

(I’m assuming this reading was taken at ambient temperature for your transmission?)

Cool, one last thing I forgot to mention – what would the ambient temperature have been for your location at the time, (I don’t know if you’re on the equator or somewhere very cold :-))