These RC circuit used on the input pins of the original ELM are for spike filtering. As they seems to miss from the clones, indeed with some ECU, spurious signals could lead to data errors and therefore failed function.
That doesn't mean, their presence will solve unworking function because of missing functionality (it won't wave the registration fee
)or wrong I/O signal connection ! As I can see the OBD connector carries extra pin used by various subsystems, thus the adapter cables. Could be solved with jumpers or an appropriate break box.
