Question about automotive components

I'm troubleshooting a Body Control Module (BCM) out of a 2003 Dodge Minivan and am noticing that all of the components (aside from the microcontroller) have no datasheets to be found anywhere on the web. Not even on their manufacturers' websites. Is it that these IC's were re-labeled specifically for use by Chrysler and that their equivalents are for sale to the public under another part number? These aren't asics or anything by any means; op amps, voltage regulators, hi-side solid state relays etc. Simple stuff. And their part #'s all end in "AA. Weird.....

Without datasheets I don't see how I'm going to be able to work on this thing....

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The automotive industry does not want you to poke around in these things. They want to sell new units, and are also concerned about safety issues(The mirror on our dodge had a label THIS MIRROR IS CURVED!!). As if you cant see that. They even might hold you responsible for any accident following your attempt to repair. However, what I see a lot around here(Netherlands) the repairman tries to pick up a second hand one at the local Cars graveyard.

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Sjouke Burry




IC's were




hi ajcrm25 i have just been through a similar experience locating datasheets on ?phantom? ICs. mine for vintage equipment that was no longer supported by oem.

i do not know the firsthand truth but i can tel you my experience/observation with locating phantom IC datasheets.

I tried searches and even contacting the original chip maker (OCM) about non-existing datasheets.

when i found a sincerely helful individual at an OCM and they received the details of the IC numbers, pics, and name of equipment the IC was in ..... they would usually reply "sorry, i have no info on that chip" or "your best bet is to contact the device maker" which sounds unbelievable as they manufactured the IC (?? confidentiality speak ??)

So it seems there are several possbilities with the phantom IC chips...

Very large companies who place very large chip orders can get their chips custom made, altered and branded in whatever fashion they desire. Sometimes there is a partial IC number relation to an existing IC usually for the more common ICs (eg. opamps, volt regulators, etc ) and then no correlation in other instances. try partial number matches on datasheet search engines (for M7101AA -> M71 or 710)

as already mention by other post, The big companies do not want the mere mortals mucking around their equiment and they do not want competitors having an easy time understanding their equipment, and probably alot of other reasons so there is a purposeful hiding of info.

to add further difficulty to the search , there seems to be a special IC chip classification just for Automotive use similar to the classification for milspec devices where even common ICs are built in a fashion to withstand harsh environments/treatment this also may include jumbling the pins around to accomodate the changes to meet the behavior and environamental specifications made by the chip buyer

so AA might be Automotive Application ? because there are extreme vibration, temperature and electrical exposures that may require a more robust IC

Example - one chip i needed (a 40 pin display driver) had a milspec equivalent where the #s were similar (eg. 75510 vs

755500) but i found out that the milspec chip had all the same pins and the same functional decription **BUT** all the pins (except Vcc, Vref) were jumbled and in completely different places. Both the chips were made by TI.

so, if you really want to dive into the BCM then you may need to do reverse / investigation ?

scope and trace out the pins, is it connected to any known ICs and then give a guess as to the function (?opamp,comparator. reg etc ?) then look up some genric version of that chip, compare pin outs to your mapping etc so forth and so on until your are reasonably sure of what the chip is and does.

if you are replacing any components you may not find common replacements with the same electrical characteristics and temperature tolerances,

any ways HTH and hope this rambling did not put you to sleep, robb

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On Sun, 6 Jan 2008 17:26:22 -0800 (PST), ajcrm125 put finger to keyboard and composed:

I have reverse engineered the FoMoCo numbered linear chips in an EEC-IV engine control module. I worked backwards from the known pinouts of the wiring harness and had a bunch of engineering bulletins to help me. These bulletins were basically aimed at the mechanic and merely gave an overview of how the unit worked. The whole job took quite some time, but I had several identical modules to repair and the jobs were ongoing. Other people have actually reverse engineered the ROM code.

- Franc Zabkar

Please remove one 'i' from my address when replying by email.
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Franc Zabkar

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