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3. Read identity

Once ECUs are registered, canair identity reads an ECU's standard identity data — part number, hardware/software version, serial number, and VIN — and decodes it for display. It queries UDS (22 F1xx) or KWP2000 (1A 8x/9x) automatically based on what the ECU speaks (see ECU protocols & PID prefixes).

canair identity MyECU
canair identity 770              # by address instead of name
canair identity MyECU --session  # some ECUs only answer in an extended session
canair identity BMS --protocol kwp   # force KWP2000 for a powertrain ECU

canair identity is a read — it displays what it finds, it doesn't edit ecus/. To capture identity for every ECU as part of the discovery sweep, use canair discover --identify (see step 2).

Why it's worth doing early

Identity tells you what each ECU actually is, which lets you rename the placeholder ECU entries meaningfully (Unknown-770 → IGPM) and cross-reference part numbers against other vehicles' known signal maps — a huge head start on analysis. Cross-referencing a shared part number with another car's public PID data is one of the fastest ways to seed hypotheses.

Recording curated identity fields

Anything you want to store about an ECU beyond the raw decoded DIDs — notes, a description — goes through the validated editor rather than hand-editing YAML:

canair pids set-identity MyECU notes "Body control module; mirrors IGPM door bits"
canair pids rm-identity  MyECU sw_version   # drop a field you filed wrongly

The field name must be one the schema declares (canlib/schema/pids_schema.yaml, identity_fields) — a typo is a validation error and the edit is reverted, so a misfiled sofware: can't sit in the profile unnoticed.

One reading, one field

Several of those fields are near-synonyms (firmware / fw_version / sw_version / sw_id, and hw_version / hw_sw) because every marque names its identity DIDs differently. Pick the one that matches what the ECU actually reported and don't mirror the value into a second field — the copy becomes dead data that later readers mistake for independent evidence. canair validate pids warns when two synonymous fields hold the same value and points you at rm-identity.

Next: 4. Scan for data →