ELAN ALDL DATA STREAM SPECIFICATION

[MKTECH]

Hello dear friends.
I'm looking for ELAN ALDL DATA STREAM SPECIFICATION

like this GM sample:

WORD BIT - DESCRIPTION - EQUATION
1 PROMISED (MSB)
2 PROMIDB (LSB) PROM = (N 1 *256+N 2 )
3 MALFUNCTION WORD 1
0 MALF CODE 24 VEHICLE SPEED SENSOR
1 MALF CODE 23 LOW MANIFOLD AIR TEMPERATURE
2 MALF CODE 22 TPS LOW
3 MALF CODE 21 TPS HIGH
4 MALF CODE 15 CTS LOW
5 MALF CODE 14 CTS HIGH
6 MALF CODE 13 OXYGEN SENSOR
7 MALF CODE 12 NO REFERENCE PULSES...

If anyone has to share I would be very grateful. Many Thanks!

[BarryDalHerbert]

I am at the very (very) early stages of investigating how a Raspberry Pi might communicate with our cars to produce ElanScan type output along with everything that happens whist driving (sort of like an aircraft's black box) as well as an alarm system, a music centre and whatever else occurs to me.

For this reason I have been poking around the Internet to find the same basic information as you have requested MKTECH, and just yesterday evening I found the two attached PDFs.
One came from here: https://MechanicBase.com/Trouble-Code/OBD1-Codes/
An the other from: https://BestOBD2Scanners.com/How-To-Read-OBD1-Codes/

I plan to hook my car up using ElanScan and see what data stream I can capture with the intention of trying to understand what I get. If there is anybody out there further down the path than my very first step, and they are willing to share what they have learned it would certainly save me a lot of time!

BdH
Tuross Head NSW Australia
30-Oct-21 13:44

[matts1972]

Hi BdH,

ALDL is great to work with as it will answer a “mode 1” request with the entire sensor data known to the ECU in one 64 byte size packet.
Feel free to use the code at ElanLogger.
It will provide most of what you require and will also answer some of your questions.
Good luck with your project!

Best regards,
Matthias

[RonR]

The Elanscan ini file contains the definitions of the fields you need, and the adjustments needed to turn the raw data into usable values.
The "Offset" and "Factor" adjustments are made in the form of addition & multiplication.

e.g. Here's the definition of Coolant temperature from the ini file:

Code: Select all

[Parameter 21]
Name=Coolant temp.
Position=6
Size=1
Offset=-40
Factor=0.75
FormatAs=%5.1f
Units=°C
Signed=0
Flags=0
Icon=25


and here's some code for getting it into usable format:

Code: Select all

byte DataBuffer[70];                      // Allow enough room for overruns
#define  Def_Offset     2                 // Offset from start of data record (-1 as array pointer starts at 0)
...
#define  DEF_CTS        6 + Def_Offset
...
   Calc_CTS = float(DataBuffer[DEF_CTS]) * 0.75 - 40;  // Calculate coolant tempature in Centigrade
#if defined(InUS)
   Calc_CTS = Calc_CTS * 1.8 + 32;                     // Adjust coolant tempature to Fahrenheit for US
#endif
...
   dtostrf(Calc_CTS,  5, 1, &CarData_ASCII[DATA_CTS]);  // Format Float as 5-byte ASCII


If a field is defined as Size=0 it's not in the ALDL data, but calculated by Elanscan.

Edit: The ini file is "M100 ALDL protocol.ini" and is usually in folder C:\Windows\

Hope this helps.

[BarryDalHerbert]

Nice!
Thanks very much for your respective input Matthias and RonR.
I now have to actually extract my digit and get going!

BdH
Tuross Head NSW
31-Oct-21 11:48

[BarryDalHerbert]

And thanks Matthias for the hyperlink to your ElanLogger project - which I somehow had managed to miss until now.

BdH
Tuross Head NSW
31-Oct-21 12:14

[MKTECH]

The Elanscan ini file contains the definitions of the fields you need, and the adjustments needed to turn the raw data into usable values.
The "Offset" and "Factor" adjustments are made in the form of addition & multiplication.

e.g. Here's the definition of Coolant temperature from the ini file:

Code: Select all

[Parameter 21]
Name=Coolant temp.
Position=6
Size=1
Offset=-40
Factor=0.75
FormatAs=%5.1f
Units=°C
Signed=0
Flags=0
Icon=25


and here's some code for getting it into usable format:

Code: Select all

byte DataBuffer[70];                      // Allow enough room for overruns
#define  Def_Offset     2                 // Offset from start of data record (-1 as array pointer starts at 0)
...
#define  DEF_CTS        6 + Def_Offset
...
   Calc_CTS = float(DataBuffer[DEF_CTS]) * 0.75 - 40;  // Calculate coolant tempature in Centigrade
#if defined(InUS)
   Calc_CTS = Calc_CTS * 1.8 + 32;                     // Adjust coolant tempature to Fahrenheit for US
#endif
...
   dtostrf(Calc_CTS,  5, 1, &CarData_ASCII[DATA_CTS]);  // Format Float as 5-byte ASCII


If a field is defined as Size=0 it's not in the ALDL data, but calculated by Elanscan.

Edit: The ini file is "M100 ALDL protocol.ini" and is usually in folder C:\Windows\

Hope this helps.

Dear friend RonR, exactly this INI file I need. Because the Serial/ALDL communication I can do successfully through the microcontroller, I just need to identify the parameter referring to each byte.
Could you please share this file "M100 ALDL protocol.ini" because I couldn't find it in my windows.

Many thanks

[RonR]

Some more details on the ECM ALDL protocol Here.
Not specifically for the M100 but a lot of GM ECUs used the same protocols.

[MKTECH]

Some more details on the ECM ALDL protocol Here.
Not specifically for the M100 but a lot of GM ECUs used the same protocols.

Really what I need is only this .INI file, because I can already do the communication through the ALDL protocol, I just haven't been able to identify all the parameters of each Byte received yet, the .INI file would help a lot to finish this study.

TKS

[MKTECH]

Some more details on the ECM ALDL protocol Here.
Not specifically for the M100 but a lot of GM ECUs used the same protocols.

I'm find now the M100 INI file. Tks for tip

[Blaster]

Have you installed Elanscan as this puts the ini file into windows. Sorry if I am stating the obvious.

[MKTECH]

Have you installed Elanscan as this puts the ini file into windows. Sorry if I am stating the obvious.

I find in: "C:\Users\MYUSER\AppData\Local\VirtualStore\Windows/'