I have some trouble understanding the pinout of my OBDII plug. It appears that it has both grounds, K-Line, 12V and CAN Bus low (according to standard obdII plug). Therefore it does not have even one complementary pair of signals. Yet, when I plug my Bluetooth OBDII scanner it communicates with ECU correctly. I have never noticed that before my ABS light came on. I was checking if in my 7th gen Civic there is a so-called Service Check System pin to force ABS light to communicate error codes in pulses. A bit puzzled by the pinout of my OBDII plug. Could someone explain the meaning of each pin? Thanks!
Generic readers decode P type errors as they're related to emissions. Your generic reader cannot decode manufacturer specific codes; B, C, and U codes requiring spending more to have a scantool similar to dealers. These scantools can provide (limited) programming coinciding with dealers access to online services of their manufacturer for updating programs when necessary. ABS generate C error codes with B and U codes for other issues. Autozone has upgraded their readers to decode abs errors so call ahead to check. Abs C codes would be something like C0045. If Autozone cannot decode your Honda abs code(s), then you might be able to force the abs indicator to flash codes by counting the number of flashes between pauses, repeating after displaying stored errors.
If I'm not mistaken, pins 2 and 5 are used for standardized (univeral P type) error codes. These are serial speed and slow. Canbus uses a different set of pinouts to connect modules in a parallel communication protocol for faster speeds. Generic readers only tap into pins 2 & 5. More expensive readers/scantools have capabilities of connecting to the other pinouts where abs codes are sent for decoding.