Hello,
I am wondering if I can read the transmission oil temperature with a scan tool, & if so what code I would look for. I know this can be done with a PDU.

I recently acquired a Ford PDU, but as of yet have not been able to acquire the Jaguar WDS software for it. If anyone has software for a GDS 3500 I would be much obliged if I could get a copy. I would of course be happy to reimburse for time & effort involved.

 

A scan tool will only read the voltage output from the Negative Temperature Coefficient sensor, a nominal 0 - 5 volts across the range. Some JATCO (the g'box manufacturer) publications give some Resistance/Voltage /Temperature relationships, but they don't seem to tie up with the Jaguar nominal 0 - 5 voltage figures.

If you need the temperature as part of doing a fluid change, you're probably better off using a hand held infra red thermometer

 

Thanks astromorg! You did divine my intent. As it turns out I do have such a thermometer & will do as you suggest.

 

Arik, you can atleast get some baseline information by letting the car sit overnight (become the same temp as the surroundings) and then using your IR thermometer, you can find the actual temp and then upon starting the car, find the voltage reading for the tranny. Not the relationship. Then, during the summer (the hotter the day, the better), do the same thing. You can even get a 3rd point say when the temp gets around 50F and is fairly constant. This way you can put the data on a piece of graph paper and figure out the slope of the line. From there, you can calculate just about every other temp you would want to know. The line should be fairly linear. YOu may find that you will get more accurate results if you can do the same temps over and over or many different temps and plot them all. You may need to do a little bit of interpolation. Worst case, get the data and send it to me. I may be able to figure out the type of temp sensor being used based on the shape of the line and be able to give some more insight to things.

 

If it helps with Thermo's suggestion, the only published figures I have to hand for this gearbox sensor are as follows:

Resist Nominal
C**F**Ohms**Voltage
0 *32**3.8*****1.8
10 50**2.74****1.56
20 68**1.68****1.32
30 86**1.25****1.12
40 104*0.82****0.88
50 122*0.58****0.72
60 140*0.43****0.56

 

Thank you both for your input. It will be interesting to suss this out. Of course it will take a while as it is the dead of winter here. I wonder if either of you have any suggestions as to the best place to take the measurement. I obviously want to always take the measurement in the same spot. Hopefully the measurement location should be as easy as possible to get to so others can use this technique once we have it figured out.

Also, it is beyond me as to why Jaguar did not see fit to put in a transmission dipstick...

 

Arik, I would tell you to take the temp on the metal line for the tranny cooler. If you look at the lower grille area of your car, if you look on the drivers side (as I recall), you will see a long cooling fine piece in front of the radiator that has 2 lines going into the end of it. That is your tranny cooler. Using the IR thermometer, take the temp off of both lines. The hotter line is the one you want to focus on as this is the temperature of the fluid leaving the tranny and more closely represents the temp of the fluid in the tranny. From there, if you need to, put a mark on one of the lines using a permanent marker or a drop of paint. Then you can get the same spot each and every time.