## Forums

#### Guest

Welcome Guest, posting in this forum require registration.

 Pages: [1] 2
Author Topic: OBD2 header for transmission temperature
copper_90680
Member
Posts: 18
 OBD2 header for transmission temperatureon: April 18, 2017 (GMT)

Hi,

Please go easy on the new guy with a stupid question.

I have a 2000 VW Eurovan and I want to get the Transmission Fluid Temperature through the ELM327+Torque Pro.

After going through the translation process to go from the X-Gauge to PID (written by someone here, I apologize that I forgot the thread, so cannot give you proper credit), I had narrowed it down to a PID 0105.

On Torque Pro, I created an extended PID as follows:

PID: 0105
Long Name: Transmission Fluid Temperature
Short Name: TFT
Minimum: 0
Maximum: 200
Scale: X1
Unit: C
Equation: A-40
OBD Header: Blank (and later on “Auto”)
The rest are blank/default

When I hit the “Test” button, it produces 2 responses:

486B104105767D
486B1A41054255

Variable A=118 (hex=76, Binary=blah blah)
Equation Step: A-40
Result: 78

Now I am absolutely certain that the first response 486B104105767D is for engine coolant temperature and second response 486B1A41054255 is for the transmission fluid temperature.

The value A seems to be the hex value of the next-to-last byte, 76 in this case. To get the correct transmission fluid temperature, I need to get the equation to use the same byte for the second response, i.e. 42.

The problem is, no matter what I tried, the equation always picked the byte from the first response so what I really got is the coolant temperature, not the transmission fluid.

I tried the OBD2 header TCM, but that gave a “NO DATA” response on Torque. A blank header or Auto header will again default to the coolant temperature.

What am I missing here? It’s so frustrating to get so close only to be stuck

Thank you and sorry for the lengthy post.

Capp777
Member
Posts: 2878
 Re: OBD2 header for transmission temperatureon: April 18, 2017 (GMT)

What protocol does your vehicle use?

cintakc
Member
Posts: 1487
 Re: OBD2 header for transmission temperatureon: April 18, 2017 (GMT)

PID: 0105
Long Name: Transmission Fluid Temperature
Short Name: TFT
Minimum: 0
Maximum: 200
Scale: X1
Unit: C
Equation: A-40
The rest are blank/default

or

PID: [fc0105]
Long Name: Transmission Fluid Temperature
Short Name: TFT
Minimum: 0
Maximum: 200
Scale: X1
Unit: C
Equation: A-40
OBD Header: Blank (and later on “Auto”)
The rest are blank/default

copper_90680
Member
Posts: 18
 Re: OBD2 header for transmission temperatureon: April 18, 2017 (GMT)

Capp777,

It’s ISO 9141-2

Cintakc,

I tried what you suggested. Still no luck.

Thank you both for responding.

cintakc
Member
Posts: 1487
 Re: OBD2 header for transmission temperatureon: April 18, 2017 (GMT)

And what answers in test mode

Capp777
Member
Posts: 2878
 Re: OBD2 header for transmission temperatureon: April 18, 2017 (GMT)

C41AF1 ? (PWM uses)
6C1AF1 ? (VPW uses)

You might be able to filter for the
correct response.

Just curious if Rx addressing will retrieve
the second line of response? (R12-40 guess).

Edited.

copper_90680
Member
Posts: 18
 Re: OBD2 header for transmission temperatureon: April 18, 2017 (GMT)

Cintakc,

In both instances, Torque responded with a question mark.

Capp777,

What is RX addressing? I think that’s what the Scanguage used with their RXF entry.

Thank you both again for helping.

Capp777
Member
Posts: 2878
 Re: OBD2 header for transmission temperatureon: April 18, 2017 (GMT)

Torque Pro also supports addressing
response bytes as R0, R1, … R12, etc
in the equation. It parses the whole
message not just the data bytes which
A, B, C, … references.

Was wondering if the second response
line was also included. (R12-40 for the
equation).

R0 would be first byte in first message
R13 would be last byte in second message?

copper_90680
Member
Posts: 18
 Re: OBD2 header for transmission temperatureon: April 18, 2017 (GMT)

Capp777,

Thank you for the explanation. That sounds promising and I will try it as soon as I am done with taxes today before the IRS comes knocking

Regards

copper_90680
Member
Posts: 18
 Re: OBD2 header for transmission temperatureon: April 18, 2017 (GMT)

Quote from Capp777 on April 18, 2017
Torque Pro also supports addressing
response bytes as R0, R1, … R12, etc
in the equation. It parses the whole
message not just the data bytes which
A, B, C, … references.

Was wondering if the second response
line was also included. (R12-40 for the
equation).

R0 would be first byte in first message
R13 would be last byte in second message?

Capp777,

I tried it and no luck. It gave weird numbers totally unrelated to what I saw in the two responses.

I tried using the header 681AF1 that Cintakc suggested, but that gave a “NO DATA”.

I am feeling like a dog seeing a steak in a cage here. Can see it, but can’t get to it.

Is there anything we can do?

Thanks

Capp777
Member
Posts: 2878
 Re: OBD2 header for transmission temperatureon: April 19, 2017 (GMT)

Did you try the header I suggested
earlier?

I thought I had read before that Ian
was saving the extra responses. Might
try running TorqueScan to see if it is
assigning an id that could be referenced
in the pid editor.

Edited.

copper_90680
Member
Posts: 18
 Re: OBD2 header for transmission temperatureon: April 19, 2017 (GMT)

Hi Capp777,

Yes I did try that header, C41AF1, but the response was “NO DATA”

Thanks

Capp777
Member
Posts: 2878
 Re: OBD2 header for transmission temperatureon: April 19, 2017 (GMT)

There are Elm327 commands for filtering
or monitoring for specific responses. Not
sure if it will work without impacting
Torque’s polling of data.

ATMT
ATMR
ATCRA (CAN Specific)

Come to mind. You might want to read up
on these to see if they could help with
getting to the correct response.

cintakc
Member
Posts: 1487
 Re: OBD2 header for transmission temperatureon: April 19, 2017 (GMT)

If you have an Android device version 5.0 and higher, go to the settings section for developers, enable logging traffic bluetooth exchange
Link to the log put here

copper_90680
Member
Posts: 18
 Re: OBD2 header for transmission temperatureon: April 19, 2017 (GMT)

Cintakc,

I have Anroid 7.0, but I do not see any setting sections for developers? Thanks.

Capp777,

Wow! I read up on the ELM327DSF doccument, and those commands are real eye openers for me. I am a Mechanical Engineer, not an EE or CS major, so I am kind of hazy, but they are still very illuminating.

Going back to my original post, there are two received messages when we transmit a request for PID 0105

486B104105767D
486B1A41054255

It seems the difference is in the third byte of the headers

486B10
486B1A

If we issue a command ATMR 1A we may be able to select the second response. Is that correct? If so, I have two questions:

1) How do we issue that command in Torque? In the Diagnostic Command field of the Extended PID?

2) Is the command ATMR1A or is it AT MR 1A or ATMR 1A?

Sorry for my ignorance and thanks a million.

Capp777
Member
Posts: 2878
 Re: OBD2 header for transmission temperatureon: April 19, 2017 (GMT)

Your posted responses were from a functional
request based upon the hex bytes. The header
I suggested earlier was an attempt for physical

I’m thinking the third byte is the transmiting
device responsible for the message but I could
be interpreting wrong?

I also believe the Elm commands will work with
or without spaces. I suggest looking at examples
in the document you found.

I’m don’t know if monitoring will affect the other
polling done by Torque.

Others have used the ATCRA with CAN vehicles but
I don’t recall any posts using the ATMR/ATMT within
the pid definition.

Since I’m weak on experience with filtering like this
I suggest reading up on the Elm commands to get
a better understanding.

Maybe someone with more knowledge can chime in?

Sure would be nice if the Rx parsing worked on both
messages received. (Hint Ian).

Just curious… there is a predefined pid 0105 for TFT.
Have you tried it? Maybe Ian addressed this already.

copper_90680
Member
Posts: 18
 Re: OBD2 header for transmission temperatureon: April 20, 2017 (GMT)

Hi Capp777,

Yes, there was a predefined TFT pid 0105 with the OBD2 headet TCM. I did try that but I got a “NO DATA” response.

cintakc
Member
Posts: 1487
 Re: OBD2 header for transmission temperatureon: April 20, 2017 (GMT)

I’m on Android 6.0.1 it looks like this

copper_90680
Member
Posts: 18
 Re: OBD2 header for transmission temperatureon: April 20, 2017 (GMT)

Hi Cintakc,

My setting displays are nearly identical to yours, except that between “printing” and “about phone” I have “legal information” instead of “developer …”

Is there a different android os for developers?

Capp777
Member
Posts: 2878
 Re: OBD2 header for transmission temperatureon: April 22, 2017 (GMT)

Copper, if you are still around, there is a
VPW form of header which uses a different
first byte (6C).

6C1AF1 ?

ISO may be similar?

 Pages: [1] 2
WP-Forum by: Fredrik Fahlstad, Version: 2.4
Page loaded in: 0.461 seconds.