Quote:
Originally Posted by Fud
Scangauge X-Gauge codes for Jeep Transmission Fluid Temperature (F)
TXD: 07E1215C
RXF: 0461055C0000
RXD: 4808
MTH: 00090005FFC5
NAM: TFT
This one seemed to work, returning a result of 160, which is in degrees F, roughly 71 degrees c. I will monitor this temp on my way home but it looks like a winner
|
Awesome!
And your CRD has the NAG1 (W5A580) ay?
The "MTH" value is the scale/offset of the original value pulled from the TCM/ECM.
It's made up of 3 2-byte fields; multiply | divide | add/subtract.
So think of it as 3 separate values; "0009" "0005" "FFC5" (which are in hex.).
The 3rd value ("FFC5") is the 2's compliment of the value to subtract.
Which is 2^16 (65536) - 65477 ("FFC5" in decimal.) = 59.
So in decimal you've got;
Multiply: 9
Divide: 5
Add: -59
Soo working back from what you've got...
(x * 9 / 5) - 59 = 160
x * 9 / 5 = 219
x * 9 = 1095
x = 121.66
Meaning that the original value coming from the TCM is "121.66" (if I did my math right.).
You could confirm that by setting the MTH to "000100010000".
I'd bet money that it's already in celsius... so there must be an offset to correct the value, which seams weird.
ie, the fahrenheit temp was being corrected by -59 DegF.
Could be due to how the temperature is calculated in the TCM, or maybe the temperature is measured somewhere "excessive", so someone decides to adjust it down to a more realistic value?
Anyway, for now if we just assume that the adjustment is need, we want to report 71.11 instead of 121.66.
So we want to subtract 50.55... doing the 0.55 would be a mess, so lets just make it 50.
x = 2^16 (65536) - 50
x = 65486.55
In hex;
x = FFCE
Soo, if you change the MTH to "00010001FFCE", you'll have the adjusted temp. in celsius.
And if you want the "raw" temp. reported from the TCM, use "000100010000".
Scangauge II X-Gauges for WH
