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Trans temp w/ OBD Fusion app and OBD2 dongle

35K views 39 replies 17 participants last post by  georgef 
#1 · (Edited by Moderator)
A few weeks ago, I noticed that one of my trans cooler lines was leaking on my 2014 T&C. I changed the lines shortly after, but I wasn't sure how much had leaked or when it started. It leaked enough fluid to make a quarter to softball-sized patch overnight each night.

When I changed the lines, I added about a 1/4 quart of trans oil. The weather was about 70 that day, so I used the 62te chart from one of the after-market dipstick makers. I measured the oil with the engine oil dipstick.

I started to notice some minor slipping and shuddering, so I got worried that it had leaked more than I thought. I bought an OBD2 dongle off Amazon and bought the OBD Fusion iPhone app and started pouring over forums to figure out how to create a PID that will read the trans oil.

So far, I've had the best luck with this one:

Module/header: 7e0
PID: 22b010
Equation: (A*256 + B)/64

**************************************************
**** Moderator's Note: The above settings are not correct
**** for OBD Fusion. See below for correct setting.
**************************************************


The readings I got from the app combined with the dipstick levels look like I over-filled the trans oil. So I pumped some out until the readings and level match the chart.

But, I am not confident in my readings. When I start the car in the morning after it has been sitting outside all night, the temperature reads about 7-10F degrees above the ambient temp. When driving, the temp will get up to 120F or so at the end of my 15-20 minute commute. It read about 140F only after two hours of interstate driving and city driving.

Here's my question(s). Can someone give me some confidence in these readings? Is there an easy (cheap) way to verify their accuracy? How could I have been less that a quarter low after at least two weeks of leaking as described above?
 
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#3 ·
Some of the things I have read say that the 62te is more sensitive to overfilling than underfilling. Some say the opposite :argue:

I didn't notice the slipping before, but now I am sweating every shift. Since I removed the fluid I think it is running better. The econ mode has always seemed rough on the transmission, tho.
 
#9 ·
How long has it been leaking? is the van still covered under any warranty. Drop the pan and do a drain and refill of the Transmission oil. Make sure sure there isn't any shavings at the bottom of the pan. When was the transmission serviced?
That suggestion is a nonsense. How can you make sure there are no shavings at the bottom of the pan? If thete are shavings, then there is nothing you can do to make sure ther are no shavings. What if he find metal shavings? Now what? Replace transmission?

Only do a ATF change if it is due for service, not because you fixed a leak.

Worst thing to do is have your transmission under-filled.

Transmission filter doesn't hold any ATF, so you don't need to add any extra ATF if you replace filter.
 
#5 ·
No leak other than the cooler lines, and repairing the lines stopped all leaking. No warranty. The slipping or hard gear changes are very minor, and they could have been there from the beginning.

I am planning on dropping the pan and doing a filter change. The recommendation for service is (I think) over 100k, but the van was owned by a rental company before I bought it from a dealer, so it has had lots of city miles, and a service would do it good.

The thing is...once I change the trans oil and filter, I still don't have a trusted way to check the fluid levels. Can I just fill it to the listed trans fluid capacity and not worry about it?

Yesterday I drove it a speeds of 55-60 for about twenty minutes, then let it sit in the driveway running for a while to get the temp up. I got a reading of 150F on OBD Fusion. I used a pump to remove some fluid from the pan, then immediately temped it with a food thermometer. The fluid in the pan was barely 100F. The hot cooler line was hot enough that I could only keep my hand on it for a few seconds.
 
#6 ·
The last time when the dealership changed my atf without touching or changing the filter they added 5 Quarts. If they changed the filter I am thinking maybe 5.5 Quarts would be needed. Keep in mind that when people changed their atf without changing filter and decided to measure what came out. Only 4 Qts 10 ounces was needed to refill what was drained.
 
#7 ·
150F trans oil temp on the freeway agrees with my van. In the winter I see 120 -140F. The vans do not have trans oil cooler in the radiator, only trans oil to air heat exchanger. So the trans runs cool. The hottest I have ever seen, 190F, was pulling an enclosed trailer in the summer.

Overfilling a trans can cause the oil to froth up and aerate. Resulting in some weird trans operation. Had that happen on Ford Focus. Dealer overfilled it by a quart. The oil would froth up and we could not get an accurate reading on the dip stick.
 
#8 ·
150F trans oil temp on the freeway agrees with my van. In the winter I see 120 -140F. The vans do not have trans oil cooler in the radiator, only trans oil to air heat exchanger. So the trans runs cool. The hottest I have ever seen, 190F, was pulling an enclosed trailer in the summer.

Overfilling a trans can cause the oil to froth up and aerate. Resulting in some weird trans operation. Had that happen on Ford Focus. Dealer overfilled it by a quart. The oil would froth up and we could not get an accurate reading on the dip stick.
This is an urban myth, overfilling can only cause ATF to leak. That might be true on engine oil, but modern oils include very good anti-foaming additives that I doubt fresh engine oil would foam.
 
#10 ·
...Here's my question(s). Can someone give me some confidence in these readings? Is there an easy (cheap) way to verify their accuracy? How could I have been less that a quarter low after at least two weeks of leaking as described above?
That is the same PID and essentially the same formula I use with the OBDLink app (same app as OBD Fusion except it only works with the OBDLink line of dongles).

Before I had the dongle I modified a temperature probe by extending it so it would fit down the dipstick tube. I compared the temperature reading between the probe and OBDLink at a range of temperatures and the readings were always within 5°F.





Modified Temperature Probe:
 
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#12 · (Edited)
...Is there any reason that mine wouldn't work as well as yours? Only reason I ask is that I read somewhere that there can be an issue converting between Celsius and Fahrenheit.
Your formula will work fine, but the app will always display the temperature in °F.

The formula I use returns the value in °C, which is the what the app expects, the "Metric to English Scale Factor" and "Metric to English Offset" take care of the conversion between °C and °F. That way the temperature will display in the units you have selected in the app settings.

From the OCTech website:
User-defined PIDs are always evaluated in Metric units. Use the Scale Factor and Offset to define the conversion from Metric to English units, when English units are configured in the app Preferences
There is more good information regarding User Defined PIDs at the OCTech website here: User-Defined PIDs

Here are the setting I use:



Note: I know there are unnecessary parenthesis in my formula, but that's the way I like it!
 
#13 ·
If you want to get fancy you can add PIDs for Min and Max fluid levels (and Nominal too).

With the help of a TI-83 graphing calculator (and my son), we came up with two quartic functions that are quite accurate at temperatures between 70°F and 200°F. Here's a graph of the functions overlaid on the fluid level chart:



These are the setting for the Min and Max Gauges:



The formulas:
Code:
MIN
.000000136*(A*4+B/64)^4-.000085943*(A*4+B/64)^3+.0199139*(A*4+B/64)^2-1.6796*(A*4+B/64)+49.243


MAX
(1-1.00000001279737)*(A*4+B/64)^4+.000012941913*(A*4+B/64)^3-.0040681341*(A*4+B/64)^2+.7883152698*(A*4+B/64)-24.31359047
Caution: Do Not round any of the numbers, dropping just one digit will result in significant error.

Note: For a nominal gauge add the two formulas together and divide by two.

And here are the gauges I use to display the information (one large gauge will four smaller gauges stacked on it):

 
#31 · (Edited)
If you want to get fancy you can add PIDs for Min and Max fluid levels (and Nominal too).

With the help of a TI-83 graphing calculator (and my son), we came up with two quartic functions that are quite accurate at temperatures between 70°F and 200°F. Here's a graph of the functions overlaid on the fluid level chart:



These are the setting for the Min and Max Gauges:



The formulas:
Code:
MIN
.000000136*(A*4+B/64)^4-.000085943*(A*4+B/64)^3+.0199139*(A*4+B/64)^2-1.6796*(A*4+B/64)+49.243


MAX
(1-1.00000001279737)*(A*4+B/64)^4+.000012941913*(A*4+B/64)^3-.0040681341*(A*4+B/64)^2+.7883152698*(A*4+B/64)-24.31359047
Caution: Do Not round any of the numbers, dropping just one digit will result in significant error.

Note: For a nominal gauge add the two formulas together and divide by two.

And here are the gauges I use to display the information (one large gauge will four smaller gauges stacked on it):

Wow! Great stuff. Your theoretical fluid levels are based upon the data provided in the chart? So, assuming you have a perfect fill of ATF, your "nominal" gauge display should accurately reflect the fluid level in the transaxle based on temp? Do you use this as a reference when checking your level with a modified dipstick? So, in essence, the gauges are a "live" representation of the table? Super cool. I run Torque in my 2ZR-Swapped and turbo Yaris for all available OBD2 data (including fuel trims, O2 voltages, intake air temp, pre/post CAT temps etc) and dedicated gauges for such things as boost, oil temp, oil pressure, trans temp etc. I just picked up AppCar diagFCA and used it to check my trans fluid level after my pan drop, filter change and refill on my recently acquired '13 T&C Limited. Again, kudos to you and your son for figuring this out! Pretty sure I'm going to try your PIDs and see if I can get it working in Torque for quick reference, rather than hooking my laptop up and using AppCar. I wonder if there are PIDs for other variables that the EVIC displays, such as oil pressure, oil temp. Out of the box, Torque doesn't draw (or interpret) much from the van's ECU, but clearly there are sensors present and data available.
 
#14 ·
Both of the formulas in this thread worked for me too, one in C and one in F.
I have some cheap bluetooth dongle off ebay, elm327 based, and torque pro.

Will be useful for towing the camper this summer. I'm hoping to get an aftermarket android powered head unit so I can have all that without needing my phone.
 
#15 ·
Georgef, thank you very much! That perfectly answered my problems. I am also now getting numbers that jive with the ambient temperature when I first start her in the morning.

I love the min, max levels. I am math-inclined (I tutor math at a college), so this made me very happy. Now, I just have to sit down and figure out how you did it!

I've always said you can't have too many parentheses. Thanks again!
 
#16 ·
I recently purchased AppCar DiagFCA software (for Windows) which can read transmission fluid temperature, so I compared the AppCar reading to the OBDLink app reading, the results matched almost exactly.

 
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#18 ·
WHOA! I really need to learn WAY more about this. I am using Torque Pro, but I have to admit, I would love to be able to read data like this tool can. Is that just adding custom PID's to it? I wanted to purchase a Wide band Module and get a gauge or just use Torque Pro for that. But as I have been reading on the BMW forums, This tool just seems to work better and the developer is more in tune with the community

Is there any video's or links to how to do this?
 
#19 ·
Trying to get this to work for my 2015 Chrysler Town and Country. I have found that I need to create my own PID to get the transmission temp, and this forum has the most information that I have been able to find. Below is the information being asked. I have filled in what has already been provided above.

Module/Header: 7e0
OBD Mode:
PID Number: 22b010
Equation: (A*256+B)/64

Thanks,

Eric
 
#20 ·
What app are you using? If it is OBD Fusion or OBDLink you should use:

Module/Header: ECU
OBD Mode: 22
PID Number: b010
Equation: ((((A*256)+B)*(1/64))-32)*(5/9)


Here is a complete list of the settings I am using with the OBDLink app:
User-Defined PID Editor
Information:
Name: Trans Temp
Description: Trans Temp
Category: Transmission
Manufacturer: Chrysler

Units:
Metric Units: °C
English Units: °F
Min Value: -20
Max Value: 160
Metric to English Scale Factor: 1.8
Metric to English Offset: 32

OBD Information:
Module/Header: ECM
OBD Mode: 22
PID Number: b010
Priority: High
Equation: ((((A*256)+B)*(1/64))-32)*(5/9)

Note: The blue entries can be changed to whatever you want.

Post #12 above has an image of how the setting look in the app.
 
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#23 ·
I have the app called car scanner that if you put in 1500 ram 2008 up theme then you get transmission temp. Different themes have different readings but I also found oil pressure as well as engine oil temp. If I want more data like misfire then it becomes a paid app for less than 5.00. I plan on buying the FCA app for 49 if I can find enough reviews but there email stated transmission data is available but at this price it is only one license and I still have 6 year warranty left so I have time.
 
#24 ·
georgef: I am trying to get this PID to work using the Torque Pro application with an OBDLink dongles on a 2009 Grand Caravan. Can you confirm what PID this should be and what OBD Header to use? (In Torque Pro, the PID field would be entered as 22b010.) In Torque Pro, the OBD Header field is to be "Leave blank, 'Auto' or HEX header. I have tried 7e0 as the OBD header, but I really don't know what is the appropriate OBD header.
 
#25 ·
I'm not very familiar with Torque Pro but I believe it has a predefined PID that you can add that will give you the transmission temperature. The PID you need is "Transmission Temp (Jeep Pre 2012)".

For details on how to add the predefined PID, see this site: The Power of Torque, find the section titled "How to Manage PIDs: Add a Predefined Set for Transmission Temperature"

These are the basic steps from the linked site:
  • From the main screen tap the settings/gear icon
  • Tap "Settings"
  • Scroll down and tap "Manage extra PIDs/Sensors"
  • Tap the menu button, the three dots on the top right
  • Tap "Add predefined set"
  • Tap "Chrysler/Dodge/Jeep/Mercedes"
You will then need to add a custom gauge to your dashboard, for the added PID.
 
#30 ·
Not that I've been able to find.
 
#33 · (Edited)
Thanks! Just picked up OBD Fusion. Will report back after I give it a try tomorrow. I may appeal to you for some assistance/tips/tricks etc. Just had a look in app and see an offering of FCA 2013 Advanced Diagnostics for $13.99. Any idea what this offers? I don't suppose this would replace my recently acquired AppCar diagFCA?
 
#34 ·
...Just had a look in app and see an offering of FCA 2013 Advanced Diagnostics for $13.99. Any idea what this offers? I don't suppose this would replace my recently acquired AppCar diagFCA?
That was just added in their last update, I suspect it is quite limited compared to Appcar DiagFCA.

60255
 
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#35 ·
Having a great time with the app. Tonight I checked the torque-based line pressures in all gears. I was super happy to see that the desired and actual lines pressures are within spec and in agreement. This is a great app!

60265


60268
 
#36 ·
Georgef...Is it possible to import this gauge you built by means of some kind of config file? I'd love to have it if you're willing to share.

60269

Thanks!
 
#37 · (Edited)
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#40 ·
Here's the formula for the nominal gauge:
Code:
(((1-1.00000001279737)*(A*4+B/64)^4+.000012941913*(A*4+B/64)^3-.0040681341*(A*4+B/64)^2+.7883152698*(A*4+B/64)-24.31359047)+( .000000136*(A*4+B/64)^4-.000085943*(A*4+B/64)^3+.0199139*(A*4+B/64)^2-1.6796*(A*4+B/64)+49.243))/2
I've also posted a link to a file, containing the gauges and PIDs that can be imported into OBDLink or OBD Fusion, here: GeorgeF's Excellent OBD Fusion Custom Transmission (post #15).
 
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