UDS request & response decoder
Interpret diagnostic services, negative responses, session timers, and DTC records from application bytes or an ISO-TP single frame.
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Read the diagnostic context.
Decode standard service IDs and common negative-response codes. Selected positive responses expose session timing, the first DID, routine IDs, and 0x19/0x02 DTC records. Values specific to an OEM or a protocol version remain raw. ISO-TP single-frame padding is removed using its length; multi-frame input must already be reassembled. Data following a DID needs its ECU definition, especially when several DIDs are present.
Negative response: 7F | request SID | NRC
Positive response SID = request SID + 0x40