This is a discussion on Tpms : $$$ within the CLA Wheels and Tires forums, part of the Mercedes-Benz CLA Forum category; No wonder ... just the admin paperwork behind these little things make them cost more than what they are composed of ... https://fccid.io/MRXMERCTX1 When you ...
2014 CLA 250: Night Black, Beige Interior, Pano Roof, Spoiler, Bi Xenons, Sport Package, Burl Walnut Wood Trim, Opticoat, Xpel, Alembic Spoiler bass, Eve IONA bass, Michael Kelly acoustic bass guitar, Gibson J40, Carvin Cobalt 750, Genz Benz Shuttle 6.2 and 6.0 amps, Two Gallien-Krueger Neo II 1X12 cabs, BOSS TU-3 tuner, Guardian of The Mighty Door Gap.
For a second there thought you were talking about an underwear commercial ........ ;-)
First I digress a tad ... though considering Schrader started getting FCC ID's in 1997 for TPMS gadgets one wonders why air pressure monitoring wasn't more common sooner but of course the excuse is cost wasn't driven down bla bla bla but of course we all know it's some bigger corporate budgets picture somewhere.
Anyway ... it seems MRX has several FCC IDs for TPMS thingies for Benz so the last thing I wanted to do was get the wrong ones and have to redo the tire mounting etc hence the little jaunt through the FCC libraries.
Then U of Michigan is the test site for engineers sending details from Ireland to get past FCC tests (at least for the MERCTX1) ... very interesting ... and the test pictures reflect the academic nature of the work which is kinda funny considering this is for the FCC and the test environment doesn't seem very controlled ... well at least not to me as it's essentially a big back yard without any electromagnetic environment consistency so Monday's results will be different from Thursday's etc (I mean gosh even most garage EE shops are more environmentally consistent). Nothing against UofM, have friends/students/colleagues there all smart hard working folks, just kinda funny how some of this FCC stuff is handled.
Not to mention some "confidential" Schrader material was left wide open for public access ... which of course they claimed it was an admin error which was later fixed (but too late -- kitties all out of the technology baggies ... then they decided to "release" some docs so I got a good look at the inside of a particular Benz class TPMS for our CLAs).
Oh well that tells me the FCC's docs / specs / regulations will need lots and lots of salt with them ... an example is one test data set was +-3dB ... kinda sad cuz that means the normalized TPMS transmitter output values were 0.5 , 1.0 , 2.0 from similar devices -- good grief ... if I had variances like that in my work I would never have been allowed to graduate ... but hey it's just a TPMS right? Who cares if the 0.5 devices drop signals and cause CELs and freak folks out? And stealerships still change like $50 for each of these things! 8-)