RE: <MISC> Y2K and ECUs <BWOB>

["JOHN FAGERLUND" <jrf@xxxxxxxxxx>]

>
>Date: Mon, 4 Jan 1999 13:57:13 -0800 (PST)
>From: chris@domain.elided (Chris Blumenthal)
>Subject: RE<MISC> Y2K and ECUs (Longish...>
>If you deal with this issue in your work as I do, you are probably sick of
>hearing about it. However, I didn't see any responses on this that seemed
very
>comprehensive...
>
>Most everyone knows that the engine management systems in later model BMWs
>consist of one or more computers, commonly known in the industry as
"embedded"
>systems. There are probably other, separate embedded subsystems in the more
>recent cars (e.g., traction control, anti-lock brakes, navigation and
security
>systems, etc.).
>

SNIP

Being the cynical engineer I am, I have a couple of questions.  In the
separate "embedded systems" you mentioned, how would the date effect their
operation?  I have written micro-controller code for a couple processors
performing real-time monitoring and controlling functions for equipment I
designed.  None of the controllers need to know what the time or date is to
do their job.

I could see if the fault codes were time and date stamped, the diagnostic
equipment may have a problem.  That is a big "IF" the faults are time and
date stamped.

Does your car know what year it is?  If the battery in your car is removed,
is there a back-up power source to maintain the time and date or does it
have to be reset?  I am not sure of this one, I have not had any reason to
pull my battery yet.

Lets clear this mess up and kill it.

Luego,

John Fagerlund
'95 540iA, BMWeee

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