RoHS, REACH, SVHC, substance compliance, material declaration, IMDS
Both apply to components sold into the European market, and both are documentation problems as much as material problems.
RoHS restricts a defined list of substances in electrical and electronic equipment: lead, mercury, cadmium, hexavalent chromium, two brominated flame retardants, and four phthalates added later. Automotive runs a parallel route through the End-of-Life Vehicles Directive, which restricts the same heavy metals with vehicle-specific exemptions, some of them covering exactly the solder and plating uses that connectivity components depend on. Those exemptions expire and are renewed, which is why a component's compliance status is a dated statement rather than a permanent property.
REACH works differently. It does not ban a fixed list. It maintains a growing candidate list of substances of very high concern and obliges suppliers to communicate the presence of any of them above 0.1 percent by weight of the article. The list is updated periodically. A part that required no declaration two years ago can require one now without the part having changed at all.
On top of both sits material data. Automotive programmes require a declaration through IMDS, the International Material Data System, and a part with no IMDS entry is a part the OEM cannot accept regardless of how compliant the material actually is.
This is one more reason paperwork matters in shortage sourcing. Stock that is genuine, in date and correctly specified still has to arrive with the declarations the programme expects, and a supplier who cannot say what documentation comes with a lot is telling the buyer something useful.
Harness Code passes on the manufacturer documentation supplied with the stock it sources, and is explicit about what documentation is and is not available for a given lot rather than implying more than the paperwork supports.
Related terms
Date code and lot code
A date code shows when a component was manufactured, usually as a year and week. A lot code identifies the production batch it came from. Together they let a buyer trace a part back through the supply chain and check that stock is genuine, recent and consistent.
Counterfeit risk and verified sourcing channels
Counterfeit risk is the risk of receiving fake, re-labelled, recycled or out-of-specification components presented as genuine. It rises sharply for parts that are scarce, obsolete or on allocation, which is exactly when buyers are forced outside their usual channels.
Approved Vendor List (AVL) / Bill of Materials (BOM)
A Bill of Materials (BOM) is the complete list of parts and quantities needed to build a product. An Approved Vendor List (AVL) names the manufacturers and suppliers a buyer is permitted to source those parts from. The BOM says what; the AVL says from whom.