Requirements for ECU tuning

User topics relating to software that provides a tuning UI to alter ECU code and data

Moderator: Freon

Requirements for ECU tuning

Postby shail2k4 » Thu Apr 03, 2008 5:42 am

Hi all,

I am new to the concept of "ECU Remapping". I am aware with the serial programming techniques.

For the ecu remapping i have gone through some literatures available over internet, but i am having some confusions listed as under.

1. The ECU must be open for remapping. -- what is that?
2. For remapping, "unclocking an ecu" is mendatory. -- what is that?
3. Is it possible to remap the data values inside an ecu without touching its software program with the serial programming techniques?
4. What is the structure of the data values stored in ecu? How can i remap the data?
5. Are there any commands to read and write data from/to ecu? If yes then is there any technical document available for that?
6. What are the hardwares required for remaping through serial connectivity?


thanx for any kind of help.

Regards,
shail2k4
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Postby Freon » Fri Apr 04, 2008 3:01 pm

We are pulling down the entire embedded flash ROM image from the ECU's microchip. To tune, you read out the image, modify it, then flash it back. This is all handled by the tactrix cable and ECUflash. The details are not terribly important if you are getting started. Basically, there is already some embedded flash utility code in the ECU and ECUflash talks to it and initiates a sequence to put the CPU into a flash mode (along with using some external connections to enable the flash mode).

There are technical documents available for the microchips we are modifying. The 32bit drive-by-wire cars use the Renesas SH-2 7055 and 7058. You can download the technical manuals for free from Renesas's website. The 16bit ECU is an HC16, but some are a special version. You can find technical documents for similar models, but maybe not the exact chip in your ECU.

You may try running some searches on this forum. There are many lengthy discussions from years ago when this stuff started on how things work. More than I could hope to find for you and repost.
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Postby shail2k4 » Sat Apr 05, 2008 2:28 am

Freon wrote:We are pulling down the entire embedded flash ROM image from the ECU's microchip. To tune, you read out the image, modify it, then flash it back. This is all handled by the tactrix cable and ECUflash. The details are not terribly important if you are getting started. Basically, there is already some embedded flash utility code in the ECU and ECUflash talks to it and initiates a sequence to put the CPU into a flash mode (along with using some external connections to enable the flash mode).

There are technical documents available for the microchips we are modifying. The 32bit drive-by-wire cars use the Renesas SH-2 7055 and 7058. You can download the technical manuals for free from Renesas's website. The 16bit ECU is an HC16, but some are a special version. You can find technical documents for similar models, but maybe not the exact chip in your ECU.

You may try running some searches on this forum. There are many lengthy discussions from years ago when this stuff started on how things work. More than I could hope to find for you and repost.


Thanx for the reply...
From this i can extract the following
1. For ecu tuning only the flash rom image file is responsible.
2. No need to completely erase the rom and reprogram.
3. All ecus are not working on a global standard.

If i am wrong then please justify.

I have gone through some image files, but they are encrypted. I tried to open that files in text editor and got bunch of characters.

Is it any kind of encryption, or special editor is required?
Source code for ecuflash is available or not?

Please help me...

Regards,
Shail2k4
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Joined: Wed Apr 02, 2008 5:35 am

Postby Freon » Sun Apr 06, 2008 10:26 am

They are binary object files. It is machine code. You cannot do anything useful with a text editor. The files posted here and the ROM images pulled by ECUflash are not encrypted.

1. Mostly yes. The flash ROM controls most engine operation. It may not control things like blinkers, electronic center differential, automatic. transmission, etc. But fueling, timing, boost control, check engine lights, yes.
2. Only the blocks that are changed are erased and written. But an entire block must be programmed from what I understand. I think there are typically 8, 16, or 32 blocks in the ECU. It varies.
3. Well, Denso supplies very similar ECUs to both Subaru and Mitsubishi. That's why the same Tactrix cable and ECUflash works on many Subaru and Mitsubishi. But it is proprietary technology. Another manufacturer, say Honda or Nissan, may do something different, but in the end it is very likely they have a flashable EPROM or emdedded flash ROM area in their ECUs. Again, there are technical documents you can typically find on the CPU itself. Like the Renesas 7055 or 7058 micro, and software manuals on how they work. You can download these from Renesas's website.
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