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Thread: Adaptation channels- explained

  1. #1
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    Adaptation channels- explained

    I was given this explanation by a colleague on another forum (thanks Mydixadryl). The explanation was authored by Sean@Revo-Technik. Does "Sean", or his alto-ego exist on this forum? If so, many thanks for the words from an appreciative student!

    The description is perhaps a little dated now (written May 2003), but it does provide a good insight into the fundamentals of adaptation channels. So a good learning tool - IMO.

    It reads like back in the days of KWP2000, adaptation channels were a minor facility (I'm guessing). With modern vehicles however, it appears that adaptation channels have taken on a more central role (as the explosion in their numbers suggest)!


    This will be an explanation of the adaptation channels in VW/Audi ECUs,
    how they can be modified, and what effect they have on engine operating
    Adaptation channels allow VW/Audi dealers to make minor tweaks to engine
    operating parameters (e.g. engine idle speed adjustment). These
    settings can be modified using the dealer's diagnostic equipment or
    These settings are stored in a serial eeprom which means the settings
    will not be lost if the ECU loses power. This is the same eeprom that
    stores data that can change from time to time like diagnostic trouble
    codes. This serial eeprom is different from the flash memory chip that
    stores the main engine control program, and therefore changes made to
    adaptation channels will not affect code checksums.

    As an example, let us take a VR6 owner who is happy with the performance
    of his engine but would like to have his speed limiter raised. There is
    an adaptation channel that can be used to raise or lower the speed
    limiter setting, and if there were a way to change this adaptation
    channel then there would be no need for this owner to even buy a chip.
    He would be able to continue running with bone stock ECU programming
    with no worries about a dealership detecting a chip (since there is no
    chip), and if he were particularly worried he would simply restore the
    default factory setting before bringing the car in for service.

    So, he connects to his ECU with VAG-COM, goes to adaptation channel 7,
    and tries raising the speed limiter. But it doesn't work: the commands
    that request the setting of new adaptation channel values have built in
    limit checks and reject the new values. In this particular case, the
    speed limiter related adaptation channel is effectively disabled since
    the stock ECU programming limits the control range so that the only
    valid value is zero (i.e. no change).

    So the issue boils down to this: is it possible to change these adaptation
    channels in such a manner that the original factory limits are bypassed?
    There are two possible approaches. First, one can make a chip with the
    preset adaptation channel limits extended to allow a larger adjustment
    range. Second, one can bypass the VAG adaptation channel routines and
    directly place the new adaptation channel settings into the ECU.
    Changing the preset adaptation channel limits in a chip is the only
    option for VAG group diesel ECUs, Magneti Marelli ECUs, and older Bosch
    ECUs. These codes check the adaptation channel limits after the values
    have been read out of the serial eeprom. Motronic 7 ECUs do not do this
    check which opens up the second method.

    Directly transferring the new adaptation channel values into the ECU
    works by finding the RAM memory location where the ECU stores the
    adaptation channel data and directly writing the changes to those RAM
    memory locations. When the ignition key is turned off the ECU enters a
    housekeeping mode where among other tasks the modified adaptation
    channel data is written into the serial eeprom. This roundabout method
    is required because memory writes directly to the serial eeprom are
    Interestingly, this method will not work using the VAG mode protocol.
    Write access is allowed to any ECU RAM location except those locations
    that store the serial eeprom data. Someone at Bosch clearly knew about
    this vulnerability and took measures to close this loophole. But for
    some reason this loophole was left in the KWP2000 routines.
    Each ECU code stores this adaptation channel data in different RAM
    locations. To make this method work with any ECU one runs through the
    following steps: 1) Establish communications with the ECU using KWP2000
    mode; 2) Read data directly from serial eeprom (since read access is
    allowed); 3) Search for this data in the ECU's RAM; 4) Write the new
    adaptation channel settings to the RAM location; 5) Cycle ignition key
    to have ECU transfer the new settings into the serial eeprom.
    The KWP2000 protocol is not as reliable as the VAG protocol. Some cars
    will have communications problems which often can be worked around by
    pulling the instrument cluster fuse (make sure VAG-COM will be able to
    clear you air bag DTC light before doing this!!!).

    Using the KWP2000 protocol gives one the ability to change settings in
    any VAG Motronic 7 ECU regardless of whether the ECU is stock or
    Last edited by DV52; 10-25-2016 at 08:01 PM.
    VW Golf MkVII (MY13) - A3 8V hatch (MY17)

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  3. #2
    Ross-Tech Employee Eric's Avatar
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    Those were the good old days
    You ain't metal till you got a clutch pedal

  4. Likes Jack@European_Parts, Uwe liked this post
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    Verified VCDS User KwiatekCh's Avatar
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    I cant see adaptation channel after diesel scandal fix !!?!?!?! anyone could help me ?

  6. #4
    Benevolent Dictator Uwe's Avatar
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    Quote Originally Posted by KwiatekCh View Post
    I cant see adaptation channel after diesel scandal fix !!?!?!?! anyone could help me ?
    It's impossible to address this question without seeing a scan.

    The engineering problems are likely insurmountable. It would be like proposing to land a rocket booster section on a barge floating in the middle of the ocean.

  7. #5
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    Is it possible to find the explanations of the adaptations of the A5 Front camera module.
    Last edited by Diver; 05-19-2019 at 09:42 AM.

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