OBDI or OBDII?



  • Maybe obd 2 has more sensors around the engine but is based on obd1 it could be that the ecu will work on obd1 as that was still in its infancy in the mid 90's. The cost of upgrading the software at dealers back then would be astronomical so you may find early obd2 was still easy to use on the old format bit like wkndows 98 and xp



  • im not sure I understand what you mean dj



  • It may be based on the same ecu but has more connectors but still compatible with thd old system



  • so whats that mean then OBD 1 or 2?



  • still trying to find an answer if anyone knows?



  • Open your ecu, if it is filled with processor chips: obd2, if you find a bunch of ic's in there, its obd1..



  • id rather not to be honest



  • Err its a cover with four screws.. nothing attached..



  • but it means pulling apart stuff as theres no easy way I could see that I could get to the bolts that hold the cage ontop of it off



  • @7037816d92=Jesta:

    but it means pulling apart stuff as theres no easy way I could see that I could get to the bolts that hold the cage ontop of it off

    Ehhm no its just a metal plate on top.. Four screws and you can lok at the internals..

    See a whole bunch of these:
    http://2.imimg.com/data2/EB/VX/MY-741063/electronic-ic-250x250.jpg
    OBD1

    Looking like these:
    http://img230.imageshack.us/img230/8789/66507he9.jpg
    OBD2



  • yeah I know, but mine has a retaining plate clamped on top of it which when I last looked was not worth the time nor effort to remove as the fastenings were unaccesible



  • Ow well, good luck then.. ;)



  • Sorry mate, but mine just isnt easily accessible, and I need my car fully functional at all times, so pulling out half the dash to find the answer of obd 1 or obd 2 just aint gonna happen, but your input is appreciated, though im disappointed that not one person on the whole forum has any idea about this.



  • Doesn't a OBD1 car have a 25pin diagnosis box and the OBD2 a 16 or something?



  • i believe that the additional pins are for a better diagnosis run from mazda, for use on their own machines so you can do stuff like fuel pump tests etc without stripping the car apart.



  • @a7b736c88c=Jesta:

    still trying to find an answer if anyone knows?

    **I can tell you that no MX-3 is either OBDI or OBDII. This isn't massively helpful, I know, but there you go :D

    The problem is that there was no "OBDI" standard - in fact the name "OBDI" is retroactively applied and wasn't referred to as that even at the time. The State of California introduced a law requiring all new vehicles sold in the 1991 model year and on to have an in-car electronic diagnosis system, largely as part of their emissions regulations, but the nature of the system wasn't specified. This meant that manufacturers all came up with their own way of doing it - how the data was stored and retrieved was not standard across the industry.

    They then came up with the OBDII standard, intended to be industry-wide, in 1994 and passed it as law in 1996. This meant that how the data was stored and retrieved would be standardised and an "OBDII" tool could read the data on any car. However, it was for "new" vehicles sold from 1996 onwards and the MX-3 wasn't one - it was an existing design and Grandfather Rights meant it could continue to be sold as it was. As it happened, it didn't sell for much longer (its sister Mazda Miata sold for another 18 months with the same basic issue) so it was irrelevant anyway.

    OBDII standards were not introduced to the EU until 2001 (as EOBD, which is largely identical), by which time the MX-3 was long since buried.

    The harness and ECU on the MX-3 is a Mazda-own "OBDI-like" (there's an in-car electronic diagnosis port, data is stored and retrieved but only by a Mazda-own OBDI-like tool) version or a Mazda-own "OBDII-like" (as above, but data storage and transfer is more like OBDII, but can only be retrieved by a Mazda-own OBDII-like tool) version, rather than OBDI or OBDII.

    This leads to massive difficulty and vagueness when identifying them, particularly as there's no really sensible way to determine the change by date (there possibly is a way to identify by VIN).

    Not helpful I know, but at least you know why it's not helpful now :lol:**



  • You have no idea how glad I am to see you pop up, and what youve said is more helpful than you know, cos I now know its a pretty pointless thing to chase after since I cant use the OBDII adapter and phone tool even if this car were OBDII due to the mazda take on things, I also know the why of that too now. So thank you for that Famine, help yourself to a Karma Jelly Bean ;)


 

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