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Re: Don't Worry-Transmission Selector Light (archive)

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Posted by Jim Cash on August 10, 1999 at 11:16:28:

In Reply to: Re: Don't Worry-Transmission Selector Light posted by Mr. Ed on August 10, 1999 at 10:45:07:

This light is an indicator that the car is "awake".

Many of the body control functions (locks, windows, sunroof, interior lighting, seat movement,etc) are controlled by a series of computer modules - all under control of the "General Module".

These all communicate with each other across the digital bus - and that takes power - not a lot, but enough that you do not want to retain this operation while the car is parked for a long period.

Soooo - there is also a "sleep" mode during which the computers basically shut down, except for a monitoring signal that goes around at a much reduces sampling rate. As soon as you open a door, the trunk, hit a remote key button, turn on an interior light, etc. this activity is detected and the system goes back into "Awake" mode.

The Awake mode lasts for about 16 minutes as long as there has been no further activity in that period.
When it goes to sleep it also shuts off any interior lighting that has been left on (glove box, map light trunk light), signals other functions to also shut down - like the little fan that vents the cabin temp sensor in the Climate Control unit.

This "Sleep" mode is also called the "Consumer Off" mode - since it shuts down power to those things that "consume" power. Basically a battery protect feature.

I think the light on the shift console is just to provide an indicator of this mode - probably more useful for someone doing fault analysis than for everyday use. I do not know if there is a similar indicator on the manual transmission cars.

Hope that helps

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