Question about automotive components

[ajcrm125]

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....

 

[Sjouke Burry]

ajcrm125 wrote:

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....
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.

 

[robb]

"ajcrm125" <ajcrm125@gmail.com> wrote in message
news:2c9c1ffd-297e-4b0c-89c7-63224cdec825@l1g2000hsa.googlegroups.com...

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....

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

 

[Franc Zabkar]

On Sun, 6 Jan 2008 17:26:22 -0800 (PST), ajcrm125 <ajcrm125@gmail.com>
put finger to keyboard and composed:

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....

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.