Shop Vehicle VIN Decode

Fills a vehicle in from its VIN using the NHTSA vPIC decoder — a free US government service that needs no credentials.

For a repair shop this beats a static catalog for data entry: the VIN is already on the car, and it resolves the exact year/make/model plus engine displacement, cylinder count, drive type and body class — the specs that actually matter when ordering parts, and which no free make/model dataset carries.

What it does

• "Decode VIN" button next to the VIN field on the vehicle form. Fills model, model year, engine, drivetrain and body, then posts a chatter entry showing what changed — a decode overwrites fields, so the shop needs to be able to see afterwards what the VIN said versus what someone typed.

• Check-digit warning. The 9th VIN character is a checksum of the other 16. A mismatch shows an inline warning but never blocks: some manufacturers don't follow the standard, and NHTSA decodes those VINs anyway.

• Batch backfill. Select vehicles in the list view → Actions → Decode VIN. Batched 50 at a time against DecodeVINValuesBatch, so backfilling an existing customer base is a handful of requests, not one per vehicle.

• Shape validation before the network call, so a typo'd VIN gets an immediate, specific message ("VINs never contain O — that's usually a misread 0") rather than a round trip and a shrug.

How model matching works

This is why the module depends on shop_vehicle_catalog: that module stamps nhtsa_make_id / nhtsa_model_id onto brands and models, and vPIC returns those same IDs. Matching is by ID, not by name.

Three attempts, most reliable first:

1. ModelID → fleet.vehicle.model.nhtsa_model_id — exact.

2. MakeID → brand, then model name within that brand.

3. Same, ignoring punctuation (NHTSA writes F-150; a catalog might hold F150).

It never creates catalog records. The catalog is module-managed data, and a model invented at runtime would sit alongside it with no provenance. When nothing matches, the vehicle's model is left alone and the decode note says what was decoded so the advisor can pick or create one.

Field mapping notes

• Fuel type. NHTSA splits this across two fields — a Prius reports FuelTypePrimary "Gasoline" like any other car, and only ElectrificationLevel "Strong HEV" makes it a hybrid. Both are consulted.

• Transmission. Core fleet only knows manual vs automatic. A DCT or CVT maps to automatic (which is what the driver experiences) and the full style string is kept in vin_transmission_style, so nothing is lost.

• vin_ prefix. Every decoded spec field is prefixed. It marks provenance on the form — these came from the VIN, not from someone's memory — and keeps the module out of the way of OCA fleet modules that add spec fields.

• Sparse decodes never blank existing data. Only keys with a value are written, and NHTSA's "Not Applicable" filler is treated as absent.

Specs land on their own VIN Specifications notebook page rather than in core's Engine group, which is gated on vehicle_type == 'car' and would hide all of it on anything classified otherwise (see the vehicle_type trap in shop_vehicle_catalog).

Configuration

Two ir.config_parameter entries, noupdate so local changes survive updates:

Decoding runs synchronously — it sits behind a button someone is waiting on, and vPIC answers in well under a second. If a large backfill ever needs to run unattended, wrap shop.vin.decoder.decode() in a queue_job.

Tests

python odoo/odoo-bin -c odoo.conf -d <testdb> -i shop_vehicle_vin \
  --test-enable --test-tags /shop_vehicle_vin --stop-after-init

26 tests, none of which touch the network: shop.vin.decoder._request is patched and fed captured vPIC responses. The fixture VINs are public samples (the Model 3 one is synthetic), and the F-150 one genuinely fails its checksum — which is how the check-digit path gets exercised against NHTSA's own verdict.

Limitations

• US-market vehicles only. vPIC decodes what NHTSA has on file; a grey-market import will return nothing and raise.

• VIN decode gives the build spec, not the current state. An engine swap or a transmission rebuild won't show up. Treat the decoded specs as the starting point, not the last word.