Originally Posted by JCMorrill
Many of the error codes you get from a Karma are related to voltage variances between the various cells. Some are more important than others. But, at this time, you need an official "Karma Laptop" to know what many of them mean.
Maybe FiskerPhilly and/or HarleyGuy can correct me if I'm wrong (and I've found that you often get more information in the form of "WRONGO FISHBREATH THIS IS HOW IT WORKS" in response to incorrect info, than you do by just asking
It's my (rather vague) understanding that the Karma, like all modern cars, doesn't merely produce a "vendor defined" error code, but also hides the real
error code off in a module that must be read using a vendor-specific "read me the real error code out of the hidden location" command. That is, your OBD-II reader will show you a P1550 which it turns out means "P1ssoff mate, we're not gonna show you the real error code unless you buy the special diagnostic system".
Otherwise, how would ForChevRysler sell all their diagnostic systems to their dealers?
All sarcasm aside, there's often good reasons (or at least, half-good) to use proprietary diagnostics, since—at least with things like the Karma—they may use some off-the-shelf parts but they combine them in "interesting" ways.