Three new reference sections: communication, brakes, body

Until today the reference sections existed only for engine codes. Forty-nine codes — every U, C and B — belonged to none: they were in the reference, but a person browsing by section never found them.

The reference can be browsed two ways: look your code up by number, or walk through the sections — «ignition», «transmission», «emission controls». People choose the second way when they do not have a number yet: they know the trouble is in the brakes and want to see what exists.

The sections, though, were built on the third character of the code — and only P codes have a meaningful third character. Everything else was left out. No check showed this: the section pages answered 200, their lists were correct, the totals matched — they simply matched against the codes that were already sorted.

What has appeared

Communication between modules — 20 U codes. The modules have stopped hearing each other; the culprit is nearly always a terminal or a ground rather than electronics. The walkthrough is «lost communication».

Brakes, ABS and stability control — 17 C codes. Wheel speed sensors, the hydraulic unit, the stability sensors.

Body, airbags and lighting — 12 B codes. With an honest warning right there: the airbag group is not to be read or cleared with random software.

The last two sections say up front that ordinary OBD-II does not read these codes on every car — why that is is covered separately. Knowing what a code named in a workshop means is useful whatever read it.

The numbers

There are now 11 sections instead of 8. The reference holds 298 codes, none outside a section and none in two at once. Every code page shows which section it belongs to.

The section check has been rewritten too: it used to compare the total against engine codes only and stayed green without noticing the loss. Now it counts the whole reference and looks at each letter separately — the overall total would also match if one letter vanished and another doubled.