Results 1 to 2 of 2

Thread: J1850 crc

  1. #1
    Newbie split63's Avatar
    Join Date
    Feb 2009
    Posts
    34

    J1850 crc

    I'm trying to create an equation to enter in to an excel spreadsheet to calculate the CRC. I'm doing something fundamentally wrong as I never get the right result.

    For J1850 the divisor is 0x1D

    So if I was calculating the CRC for 61,6a,F1,01,00

    wouldn't the answer be =~(616af10100-INT(616af10100/1D)*1D)
    This finds the remainder of 616af10100/1D and then takes the ones compliment.
    The answer should be 0x0A, the above gives 0xF9

  2. #2
    VENDOR - ScanTool Vitaliy's Avatar
    Join Date
    Dec 2006
    Location
    Phoenix, AZ
    Posts
    624
    split63,

    That's because the formula you're using is wrong. The algorithm to calculate CRC is a bit more complicated than that.

    There is code out there, than can calculate the CRC for you, for instance:

    http://obddiagnostics.com/obdinfo/CRC.txt

    Vitaliy
    OBDLink MX: world's smallest, fastest, most advanced OBD/Bluetooth adapter with SW and MS CAN support. Read the review to learn more.
    Need to look up a diagnostic trouble code? Try the most up-to-date, free DTCsearch.com!

    You cannot send me a private message using this forum. Use my email instead: vitaliy[@]scantool.net.

Similar Threads

  1. Alpine AINet CRC solved
    By viper_1 in forum Car Audio
    Replies: 217
    Last Post: 03-19-2014, 08:36 AM
  2. Ford J1850 PWM
    By plisskin in forum Engine Management, OBD-II, Engine Diagnostics, etc.
    Replies: 23
    Last Post: 12-23-2010, 01:33 PM
  3. CRC calculation
    By tom_rosenback in forum Coders Corner
    Replies: 3
    Last Post: 11-17-2008, 04:16 PM
  4. J1850 PWM specs
    By interceptor in forum Engine Management, OBD-II, Engine Diagnostics, etc.
    Replies: 5
    Last Post: 11-17-2008, 11:53 AM
  5. PWM j1850 response 0x10
    By Juan Wortley in forum Engine Management, OBD-II, Engine Diagnostics, etc.
    Replies: 0
    Last Post: 11-04-2005, 02:56 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •