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January 18, 2020, 05:57:08 PM
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Author Topic: how does the sportshift know what to dislay for a gear ?  (Read 3278 times)

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Offline wheelbuilder_25

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how does the sportshift know what to dislay for a gear ?
« on: April 18, 2013, 02:15:59 PM »
I'm curious if it would be possible to have the display show what gear you're in all the time?  On the 4EAT it shows when you are in sportshift mode.  There has to be some output from the tranny to indicate that.
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Offline BlackParis

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Re: how does the sportshift know what to dislay for a gear ?
« Reply #1 on: April 18, 2013, 04:38:37 PM »
I'm curious if it would be possible to have the display show what gear you're in all the time?  On the 4EAT it shows when you are in sportshift mode.  There has to be some output from the tranny to indicate that.

That's a good question :-p

Ur saying it jut shows a D when your in drive, and you want it to tell u what gear your in.

It probably has to do with programming inside the transmission control module. Not any way really to go around that unless you can decode the TCM
« Last Edit: April 18, 2013, 04:40:32 PM by BlackParis »
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Offline wheelbuilder_25

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Re: how does the sportshift know what to dislay for a gear ?
« Reply #2 on: April 18, 2013, 08:20:08 PM »
I've looked in the service manual, and I don't see where it's pulling the info from.  Where would I find info on the TCM ?
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Offline hydrochloric

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Re: how does the sportshift know what to dislay for a gear ?
« Reply #3 on: April 19, 2013, 11:04:28 AM »
Is it possible it's just running an algorithm based on RPM and wheel speed?  The TCM would have both of those inputs.
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Offline FastfreddyRs

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Re: how does the sportshift know what to dislay for a gear ?
« Reply #4 on: April 19, 2013, 01:33:57 PM »
You need to read the wiring diagrams for the 4eat.  The range switch on the trans sends signal to the tcm which sends the output to the body integrity module which sends the info to the cluster
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Re: how does the sportshift know what to dislay for a gear ?
« Reply #5 on: April 19, 2013, 01:41:41 PM »
You need to read the wiring diagrams for the 4eat.  The range switch on the trans sends signal to the tcm which sends the output to the body integrity module which sends the info to the cluster

... and there it is.
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Offline wheelbuilder_25

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Re: how does the sportshift know what to dislay for a gear ?
« Reply #6 on: April 19, 2013, 01:50:46 PM »
Thanks, I'll try to dig that up.  I know its fairly trivial to have that display, but it seems like it should be do-able.
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Offline BlackParis

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Re: how does the sportshift know what to dislay for a gear ?
« Reply #7 on: April 19, 2013, 09:35:16 PM »
You need to read the wiring diagrams for the 4eat.  The range switch on the trans sends signal to the tcm which sends the output to the body integrity module which sends the info to the cluster

So he would need to figure out the programming if body integrity module?

If the range says he is in drive. Then it's output will be D. But if the range is sport shift then it displays the gear.

I really don't think this would be a simple wiring thing.
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Offline FastfreddyRs

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Re: how does the sportshift know what to dislay for a gear ?
« Reply #8 on: April 20, 2013, 09:45:34 AM »
from what i saw in the wiring diagrams yes, it looks like it wont be a matter of cut one wire and swap it.  since all of the inputs for the sensors. ( sport mode switch, range switch) are before the Body integrity module. 
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Offline wheelbuilder_25

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Re: how does the sportshift know what to dislay for a gear ?
« Reply #9 on: April 20, 2013, 11:00:43 AM »
The diagram I have just shows a block labeled 'microcomputer' between the display and the BIU, so that must be doing the translation.  I suppose I could bust out the ocilliscope and see what the signal looks like.
Does the BIU speak any common sort of protocol ? (ethernet would be great, but serial data is easy enough to sniff off the wire too)
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