4L80E / ALDL

[Ward Spoonemore]

I thnk your project has merit, I also think the PIC chip is a winner for
this kind of application.
How bout dumping the data to a flash chip for use later, the real time
display is of limited use and you can eliminat all the junk in the the
truck.

I can probably help with the decoding, Ill check back.

Ward

> -----Original Message-----
> From: owner-diy_efi at efi332.eng.ohio-state.edu
> [mailto:owner-diy_efi at efi332.eng.ohio-state.edu]On Behalf Of Niinikoski
> Juha
> Sent: Friday, March 05, 1999 4:45 AM
> To: 'DIY_EFI at efi332.eng.ohio-state.edu'
> Subject: 4L80E / ALDL
>
>
> Hi
> I am new on the list and don't know if this is right place to start 4L80E
> TCM thread ?
>
> I have 97 N/A diesel Hummer with 4L80E electronic transmission. Some time
> ago I decided to try to build a display unit with what you can watch few
> most critical transmission parameters like temperature TCC slippage and
> possible clutch slippage. So far I have managed to hack ALDL interface and
> protocol. Of course this happened by the hard way. First I taught that
> Hummer 97 Implementation where OBD-II because of OBD-II like connector but
> it is ALDL 8192.
>
> I have build couple of display prototypes. One with Motorola HC12 CPU and
> 4x40 LCD display.HC12 contains also 8-channell A/D converter. I
> have plan to
> include some other measurements too.  Second one is really cheap
> build with
> Microchip PIC16F84 "washing machine" processor and 2x20 LCD. If anybody is
> interested I can provide more information about my projects.
>
>
> Where I need help.
> 1.
>  I am now stuck with decoding parameters what TCM provides. I have found
> most easy / evident ones like RPMs, temperature, selector
> switches etc. Most
> of the response data is still unknown for me. Do anyone have documents or
> more information about 4L80E ALDL commands / responses ?
>
> 2.
> What is the right way to start communication with TCM. I have figured out
> that read parameters command is F5 57 01 00 B3 but you need to
> give command
> twice first time. After ALDL bus have "woken up" you need only one command
> to get response. If you do not issue new commands within about one second
> bus goes to sleep mode again. Are there some sort of wake up
> procedure or is
> this (sending first command two times) right way to do it ?
>
> Juha Niinikoski
> Espoo Finland
> 97 N/A Diesel Hummer
>