OEM EMC Specifications

Editors note: This article is a compilation of several e-mails that the Automotive EMC network has received from subscribers on the topic of OEM EMC Specifications.  It has been edited into a single article by the newsletter editor but is not the original work of AutoEMC.net.  We would like to thanks those contributors and hope this piece reflects the issues about OEM Standards they intended to raise in writing to AutoEMC.net.

Obtaining OEM Specifications

The main question raised on the Automotive EMC network is "Can you supply the EMC Specification from XYZ Motor Co.".  It is something the Automotive EMC network would be delighted to be able to supply but unfortunately to date our requests to host OEM standards has fallen on deaf ears.

The Good

In the arena of EMC Specifications, one OEM stands out as being the most open and liberal provider; Ford.  The Ford Motor Company have provided a dedicated website where their EMC standard, their installation guidelines and a list of approved test houses can be viewed or downloaded (www.fordemc.com).

Among others OEM's General Motors (GM), Peugeot-Citroen (PSA), BMW, FIAT and Lotus are relatively easy to approach and, in the experience of AutoEMC.net subscribers, provide their specifications freely (FIAT and Lotus may by now be using the GM specification).  The main difficulty with this group is knowing who to contact.  Their websites provide very little in the way of access to their technical services (other than commercial vehicle services) and it is most likely a deliberate omission to avoid a mass of customers requesting data they don't need and in many cases would not understand.

The Bad

Especially poor for providing data are MG Rover, Renault, Daimler-Chrysler (DC) and Volkswagen-Audi Group (VAG), these companies have rejected some subscribers requests if they are not already a Tier 1 or 2 supplier and in some cases simply ignore any efforts to discuss the issue.  The case of Renault appears to be a reverse creep of a symptom of many Japanese OEM's (see below) after their acquisition of Nissan. 

In the case of DC, despite the time that has elapsed since the merger of these companies, it seems to be a case of split responsibilities and no one site appears to want to be found guilty of providing information.  This is a particularly sad situation as the previous independent specifications of Chrysler and Mercedes-Benz were good specifications that were relatively easy to obtain.

The Impossible

The most secretive companies with respect to EMC specifications are the Japanese OEM's.  It appears this is a cultural issue and the provision of this information is seen as potentially highlighting weaknesses in companies' vehicles.  While in the West an EMC specification is seen as good engineering practice, in the East it would appear as a competition and the company with the "easiest to meet" EMC specification may be seen as somehow inferior to those with more stringent requirements.

A Request to OEMs

The Automotive EMC network would be delighted to host any OEM specifications for the use by professional automotive electrical/electronic design engineers and EMC test engineers.  If the OEM's feel they can not provide the specifications outright, as Ford have, then at least let this site provide contact details to enable our subscribers to contact the appropriate departments within your company.  If you can either provide a specification for hosting on this site, or a link to the appropriate location, or contact within your own organisation please send details to news@autoemc.net.

The Test House Dilemma

The lack of easy access to some OEM specifications causes a dilemma for test houses, how do they advertise the fact that they can test to an OEM specifications if they can't obtain a copy, or if they already have the specification but they are not allowed to provide details.  Conversely how can a customer request testing to a specification if they are not allowed by an OEM to provide the specification with the test documentation.

With international standards it can be expected that the test house will have, or can easily obtain, all the relevant specifications.  But with a customer specification it is different and we have heard of a situation where an OEM has not allowed a supplier to provide their EMC specification to a test house, and has then refused to supply the test house directly as they are not a supplier to the OEM!  This is a restriction of trade, preventing test houses not approved by the OEM from even performing pre-compliance tests. 

The Ford approach should be used as a model of good practice for all OEM's; the specification itself is freely available and then additionally Ford audit and approve a number of specific EMC test houses.  This allows a supplier to have the early development and pre-compliance work done wherever they wish, then final compliance testing via an approved test facility.

The Design Consultancy Dilemma

There are many dilemmas for design consultancies from restricted access to OEM specifications.  The first is providing adequate training for their staff on the requirements of the OEM’s and what design practices might be needed to meet certain parts of their EMC specifications.  The consultancy could use these specifications to estimate cost additions to a product from OEM-to-OEM (if this is necessary).  At the quotation stage for a project the consultancy would have a better estimate on where they are likely to have problems and which test houses they are going to be able to use.  This would benefit the client as well as the consultancy as it should improve the accuracy of the initial quotation.

Few design consultancies could be drawn on this issue as they do not want to “rock the boat” with OEM’s, but many did express problems with obtaining OEM EMC specifications, even when these specifications were listed as a design requirement in the initial request-for-quote document.  It appears once the contract is awarded the specifications are easier to obtain, but by this time it is too late to correct for any anomalies in the quote due to EMC requirements.

The Commodity Supplier Dilemma

This dilemma is a relatively easy one to conceive, if you make ABS systems for example you want to make one system to meet all specifications, but today that is very difficult and due to other factors is probably impossible.  Even so, when first approaching OEM's it would be useful to have a test result saying "this is where we are in relation to your EMC requirements" and then determine what else needs to be done to meet the requirement, or what costs can be saved because you exceed the requirement.

The situation with aftermarket products is potentially more problematic and few aftermarket suppliers are familiar with OEM specifications.  The minimum legal EMC requirement is relatively easy to meet compared to the OEM specifications.  It would be beneficial to both the producer who is looking to obtain OEM fit at some stage, as well as to the consumer, to know that an aftermarket fit product met the full EMC requirements of specific vehicle makes.  This could be a selling point for these products and a potential safety feature.

The OEM Dilemma

Why should an OEM supply this information freely?  They need only provide it to their current supply chain.  Making it freely available opens the documents for scrutiny by all-and-sundry and any minor mistakes might be picked upon as poor error checking.  The specification is a proprietary document and may be open to interpretation, hence a supplier might claim to have met the requirements, but because of the application they have failed to apply stringent enough tests according to the OEM.  By restricting access to the EMC specification the OEM can ensure that pattern electrical parts are difficult to produce without the OEM’s approval, hence ensuring that the electrical safety is tightly controlled.

OEM’s all run strict quality systems and one problem of making the specification freely available is ensuring that anyone wishing to supply to the specification has the correct and most up-to-date issue.  By restricting the circulation the OEM can ensure that there is tight document control and circulation of their specification without having to actively advertise new issues to ensure the marketplace is aware of changes.

Editors Note: Do you agree with this article or is your experience different to those reported by some of our subscribers?  We would like to hear any war stories or good practice stories with relation to OEM EMC specifications.  We would also like to hear from OEM’s and report any progress on obtaining their EMC specifications, or arguments as to why they should not provide them.  Send comments to news@autoemc.net.


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