Modify ELM327 to add the HS/MS CAN switch

ELM327 works with HS CAN from the stock, because Ford HS CAN completely matches to the OBD2 standards. It occupies pins 6 and 14. MS CAN bus occupies pins 3 and 11. The picture below illustrates the thing (ATTENION: the OBD2 jack on the picture means vehicle one, “female”. The adapter’s one is “male”, so it is “mirrored”. Pins are often mixed up because of this. Always note pins’ numbering of the adapter’s jack!):

Ford_OBD2-01

The simplest way to implement the MS CAN support is to add a switch that will shift between MS/HS CAN. The scheme below explains the modification (ATTENION: the OBD2 jack on the picture means vehicle one, “female”. The adapter’s one is “male”, so it is “mirrored”. Pins are often mixed up because of this. Always note pins’ numbering of the adapter’s jack!):

elm-mod-02
Roadmap:

Purchase a 6 pin mini-switch of ON-ON type (for example, MTS-202-A2) in any shop that sells electronic components, also prepare a wire

MTS202-03
Disassemble ELM327 (for majority of china clones – carefully remove the label that hides 4 screws, unscrew them)
Find a place for the mini-switch (most complex part of the whole operation for some devices that are extremely compact)
Unsolder wires from pins 6 and 14 of the OBD2 jack and solder them to the 2 middle pins of the mini-switch
Solder 2 new wires from 2 outer mini-switch pins to pins 6 and 14 of the OBD2 jack
Solder 2 other new wires from 2 other outer mini-switch pins to pins 3 and 11 of the OBD2 jack
Check the work (it is very important to do not mix CAN-L and CAN-H wires up!) and assembly the ELM327, mark the MS and HS can position on the device box to avoid confusion

Example of the modification for ELM327 USB plastic:

ELM327_HSMS_example-04

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