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Discussion Starter #1
Hi Fellow X-men:
I've had my X for about 7 months and love the thing. However, I have not done my bypass as yet as it is very hot where I live all year round, and as I understand it, besides SMOD, the other tranny killer is heat.

I'm paranoid about SMOD as I check ATF and coolant weekly but all is clean and clear for now, but I really want to bypass and put a fan on the transmission cooler and I want to monitor my trans temps. (I probably don't even need the fan since I don't wheel nor tow).

Ok so I observe on the forum that the torque app does not show our trans temp, but the Bullydog does. This leads me to believe that it is possible for the torque app to also get this information from the OBDII port.

For extra PID's that are exclusive to your make and model, Torque offers the ability to put your customized PID.


After some research, I see that the PID for transmission temp is P0710, I came across this in the Engine Control Service Manual, as shown below.


So I'm almost there, but I'm stuck where it asks for an equation as shown below. Does anyone have any idea whatsoever what goes here?



Thanks
 

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My best guess (in working with a couple other ODB-II readers) is that the equation tells the app how to take the reported value off the ODB-II bus/port and convert it to a readable value that makes sense.

For instance the MAF sensors puts off voltage readings, which can be converted into AFR values via an equation.

Anyway - what happens if you just have it display the value off the sensor? (I'm guess '0d'). Does it come over as voltage? An actual temp reading? Or something else?

FYI - Others on the site have said that the Bully Dog lists 275 degrees as 'limp' mode for the transmission or an overheat condition.
 

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Discussion Starter #3
I agree that makes sense, I have not tried it with a default value or anything but I will try it on my lunch break and report back if any value comes up.

as a reference: Toyota guys got it working with the below.
OBD2 Mode & PID: 21D9
Long Name: Transmission Temp
Short Name: Trans T
Minimum Value: 0
Maximum Value: 300
Scale Factor: x1
Unit Type: *F
Equation: ((((E*256)+F)*(7/100)-400)/10)
OBD Header: left blank

I am just not sure what the variables (E and F) shown above represent.
 

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Would be awesome if you could get this to work!!!
 

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Discussion Starter #6
I tried it but no such luck as yet.


In your sig I see you have uprev, is that table to read transmission temps?

This Guide gives a fairly good explanation of what the variables represent: http://torque-bhp.com/forums/?wpforumaction=viewtopic&t=352.0

The user is using info about the PID from ScanGuage and is importing it into Torque.

This tutorial references the following 2 PDFs;
http://www.scangauge.com/support/pdfs/XGAUGE.pdf
http://www.scangauge.com/support/pdfs/XGaugeCoding.pdf
We need to fill in the following fields on Torque

OBD2 PID
Long Name
Short Name
Min Value
Max Value
Scale Factor
Unit Type
Equation

with the following from SGII

GAUGE
TXD
RXF
RXD
MTH
NAM
NOTES

As we go through the tutorial I will use the following for an example
Engine Oil Temperature 07E0221310 046245130610 3010 00090005F05F EOT Degrees F

OBD2 PID
This field comes from the TXD of the SGII file. There are 2 flavors, CAN (controller Area Network) and the rest of the older OBD2 protocols. If it is CAN, you want to use all the characters after “07DF” or “07E0”. If it is “07E1”, then Torque will likely not work for this gauge as the ELM327 may need specific instructions to communicate the transmission control module.
For all the other protocols, you want to use all the characters after the “F1”.
Our example: 221310

Long Name
Take this value from the GAUGE field
Our example: Engine Oil Temperature

Short Name
Take this value from the NAM field
Our Example: EOT

MIN/MAX
These are really determined by the data you are gathering and can be set up after you have your equation. Torque does a pretty good job of rescaling gauges if the data over steps the range.

Scale Factor
I always leave this as 1 because we can scale in the equation if we need to. However, SGII may do some prescaling that you should be aware of before you implement your equation.

Unit Type
Take this value for the notes field
Our example: F

Equation
Now for the most complicated part.
First look at the RXD field. Don’t worry about the first 2 characters. If the second 2 characters are “08”, then you have 1 byte of data and you will only need an “A” in your equation. If the second 2 characters are “10”, then you have 2 bytes of data and you will need to start off your equation like ((A*256)+B). Don’t ask why. This isn’t a lesson in hexadecimal.
Our example: “10”-> ((A*256)+B)

Now look at the MTH field. It is separated in 3 sections. It may look like this 00090005F05F. The first 4 characters (0009 in our example) are the multiplier. These values are in hex so you must convert them to decimal. Open up the windows calculator and makes sure it is set to scientific view. Click the hex circle and enter in the first 4 characters. Then click the decimal circle. The value displayed is what you want to use in torque. Repeat this step for the second 4 characters (0005 in our example) and you will have the divisor. The final four are the trickiest. If you have an F,E,D,C,B,A,9,8 as the first character as we do in our example, then this will be a negative number. To calculate this use windows calculator and set it to HEX. Enter the value and click XOR and enter “FFFE”. Click “=”, then click the decimal circle and you will see what value you have to subtract from the equation. If there isn’t, then we will be adding this value. And you proceed the same as with the multiply and divide to the value.

Our example: 9/5-4001
The final thing to pay attn to is the RXF field. Which may look like 046245130610. Pay close attn to 0462->4-5130610. If you see a 4 here, then your data must be multiplied by 100. If you see an 8, then your data must be multiplied by 10. If it is 0, then don’t worry about this part.

Our example: *100
Final equation: ((A*256)+B)*100*(9/5)-4001

This is only a guide and not a bible. If you can’t get data for a PID it can me two things, you entered it wrong or your car doesn’t support it. Just b/c your car as a certain sensor it does NOT mean your vehicle will support the PID to get that data.
 

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I didnt have a chance to plug into the car, but I took a look at the UpRev software I have installed and re-visited the manual.

From what I can tell in the manual, it appears UpRev does not have the ability to pull custom values.

I will validate when I can plug into the car and re-visit the gauge list that it does have, but from what I recall there was no example of transmission temps.

Reading the below, it appears that someone used a ScanGauge that had transmission reading capabilities on their vehicle to then mirror the values that would be require to utilize the Torque app.

The only known ODB-II reader for the Xterra that gathers transmission temps is the Bully Dog tuner. I can't comment as I don't own one and don't have experience with one. Perhaps someone with a BullyDog can chime in, if there is a configuration menu to see HEX values that it used to determine transmission temps.



I tried it but no such luck as yet.


In your sig I see you have uprev, is that table to read transmission temps?

This Guide gives a fairly good explanation of what the variables represent: http://torque-bhp.com/forums/?wpforumaction=viewtopic&t=352.0

The user is using info about the PID from ScanGuage and is importing it into Torque.
 

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Discussion Starter #10
Slightly Off topic, what interface are you using to connect the phone? I need this...
This in particular is what I use in conjunction with Torque app.
http://www.amazon.com/BAFX-Products-PIC18F2480-diagnostics-compatible/dp/B005NLQAHS/ref=sr_1_2?ie=UTF8&qid=1377273470&sr=8-2&keywords=odb

I didnt have a chance to plug into the car, but I took a look at the UpRev software I have installed and re-visited the manual.

From what I can tell in the manual, it appears UpRev does not have the ability to pull custom values.

I will validate when I can plug into the car and re-visit the gauge list that it does have, but from what I recall there was no example of transmission temps.

Reading the below, it appears that someone used a ScanGauge that had transmission reading capabilities on their vehicle to then mirror the values that would be require to utilize the Torque app.

The only known ODB-II reader for the Xterra that gathers transmission temps is the Bully Dog tuner. I can't comment as I don't own one and don't have experience with one. Perhaps someone with a BullyDog can chime in, if there is a configuration menu to see HEX values that it used to determine transmission temps.
I agree, until we understand how Bullydog is able to do it, seems we're dead in the water.:scratch:
 

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This would be great - even tho I have a MT and no trans temp sensor.

You might try sending a PM to Mrcole - I believe he has some experience with OBDII communication.

The PID value is not the same as the problem DTC - so 0710 isn't going to work.

My little understanding of OBDII and CAN bus is that the chip in the bluetooth module actually requests certain parameters from the bus and then they are returned - so without knowing the proper HEX code to request the correct reading, you're just kind of guessing in the dark.

Start with finding the HEX - once it returns a value... any value. Then determine if it's in volts or degrees and we'd have to manually come up with an equation to convert it.
 

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Discussion Starter #13
Thanks you have helped me to understand OBD a bit more.

I see that a guy at Club Frontier found the values for adding them into ScanGuage but no one has reported if it works or not.

http://www.clubfrontier.org/forums/947656-post6.html

and here the user seems to be getting a value but perhaps his formula is giving wrong values.

http://www.clubfrontier.org/forums/1086229-post19.html

I will try them later this evening when I get home by extracting the hex values using the writeup I posted a couple posts back and see if I can at least get some values.

Seems all is not lost.
 

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Discussion Starter #14 (Edited)
Try the app - TorqueScan

Apparently it allows you to scan for extra PIDs. I'm just not sure how you will identify which one is your trans temp...
Yeah I have torque scan, It does not actually scan for PID's but just displays all values (PID's delivered in the app) on one screen.

EDIT!

I see that it actually can scan and look for extended but I was unaware of this functionality. Will definitely try this also.

I am assuming that I will use "TCM" as the obd header so that it only scans the Trans..
 

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Yeah I've been doing some reading on this - the "full" scan of the PIDs can take over an hour so make sure you have a good battery charge if you do it.

The problem is you may find it - but it might not be in degrees and it's hard to verify you are looking at the right PID. I guess you would need to do some driving and compare to a bullydog for each one you find.
 

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Discussion Starter #16
Just a slight update:
I've tried the values that I've posted some comments back, but they were unsuccessful.

In terms of the PID scan, I let it run for 30 minutes before I gave up and quit scanning. There was no successful PID's discovered in this time. The engine has to be running when scanning.

I will do a full scan when I have a long trip, but I can't have it running in the drive way for 1+ hours.

Perhaps someone who has torque can do a full scan if they are going to do an 1+hr long trip.
 

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Discussion Starter #18
Over this past weekend, I had a 90 mile trip and decided to scan for PIDS.

I did the quick scan first and got this result:
Please enter the vehicle type if sending to the developer, thanks!

Command: 2401 response:
BUS INIT: ...OK
STOPPED
Command: 2402 response:ELM327 v1.5
Scanning was cancelled
Scanning finished
This "quick scan" took about 40 mins.
So this gives me PID's 2401 & 2402 to check out.

After this is completed I attempted the fullscan and got this.

Please enter the vehicle type if sending to the developer, thanks!

Command: 2401 response:
BUS INIT: ...OK
STOPPED
Command: 2402 response:ELM327 v1.5
Scanning was cancelled
Scanning finished
Command: 220009 response:STOPPED
Scanning was cancelled
I didn't complete the scan, but I see that it picked up an extra PID 220009.

Alright so I got home, shut down my engine and went back to see if I could get any values for these PID's and .... nothing.

Ran the scan again and got no results like i previously had. (2401 and 2402 are the first PID's scanned by the utility and nothing came up for them this time)

My feelings are that sooner or later we'll be able to get this but it takes a lot of time.
 

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Over this past weekend, I had a 90 mile trip and decided to scan for PIDS.

I did the quick scan first and got this result:


This "quick scan" took about 40 mins.
So this gives me PID's 2401 & 2402 to check out.

After this is completed I attempted the fullscan and got this.



I didn't complete the scan, but I see that it picked up an extra PID 220009.

Alright so I got home, shut down my engine and went back to see if I could get any values for these PID's and .... nothing.

Ran the scan again and got no results like i previously had. (2401 and 2402 are the first PID's scanned by the utility and nothing came up for them this time)

My feelings are that sooner or later we'll be able to get this but it takes a lot of time.
Keep fighting the good fight man! I just ordered my obd2 deal yesterday. I'm bypassed in the desert of NV so atf temp is a major concern of mine as well:iconbiggrin:
 

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Something you may want to try is use the device, i.e. the BullyDog Tuner with your Xterra and read the PID requests from the BullyDog. If it were me I would use a Vector CANalyzer tool (expensive$$$) or a PCAN tool (less expensive) inline with the BullyDog to sniff the CAN bus and capture the PIDs. I would then run a comparison to the standard J1939 list and through a process of elimination determine what PIDs do not appear on the list and go from there (also all known Nissan-specific PIDs). Another path, and more difficult, would be to track down some Nissan SW engineers. Those guys always hang on to dbc files (CAN dictionary files) for the vehicles they work with. I work with several engineers that have dbc files from old jobs that encompass several vehicles. I plan to eventually get a BullyDog and can capture some data with a CANalyzer tool when I do.
 
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