TCM Reverse Engineering Project

[olk93]

@wowser could you quick explain how the graph does look like?
Is the graph a function or a relation?

Lets take a random table (from 89tcm-678), eg.

;mptbldesc Desc_T80BC
.byte 0x04 ;Number of points in table
.byte 0x29, 0x00 ;Point 1
.byte 0x29, 0x1C ;Point 2
.byte 0x4E, 0x68 ;Point 3
.byte 0x4E, 0xFF ;Point 4

Relation : y-coords of point 1 = 00 and point 4 = FF then the graph would look like a right-angled trapezoid (turned ccw 90^).
Function : coords of point 1 = 00,00 and point 4 = FF,FF and points 2 and 3 literally as above?

short: if point 2 is x = 29, y = 1C and point 3 is x = 4E, y = 68 then what are the coords of point 1 and 4 ?

(sorry if the format of this sort of tables is allready explained in another post, but i have not found any explanation yet)

[wowzer]

it's basically a step graph and sloped graph. pretty straight forward really. e.g. using the data in this table...

input to the table is in A. result comes back in B.

assumptions: starting coordinate is (0x00,0x00), last coordinate is (0xff,0xff)

00 <= A <= 0x29 b= (A - x0)/(x1 - x0) * (y1 - y0) + y0 = 0x00
29 < A <= 0x4E b= (A - x2)/(x3 - x2) * (y3 - y2) + y2 = value between 0x1c and 0x68
4E < A <= 0xFF b= (A - x4)/(x5 - x4) * (y5 - y4) + y4 = 0xff

so basically the graph points would be:
x y
0-(0x00,0x00)
1-(0x29,0x00)
2-(0x29,0x1c)
3-(0x43,0x68)
4-(0x43,0xFF)
5-(0xFF,0xFF)

i need to finish setting up mptune to be able to display this correctly.

[olk93]

Thats cool. Now i understand better. Thanks for sheding a light on this.

[Force Fed Mopar]

So excited...

So, to get a new calibration onto the TCM, I'd have to socket it, right ( or use a flash module)? Not currently a way to flash to a TCM through the factory wiring?

[ShelGame]

So excited...

So, to get a new calibration onto the TCM, I'd have to socket it, right ( or use a flash module)? Not currently a way to flash to a TCM through the factory wiring?

Depends on the year. The older units are factory flashable. But, I started dis-assembling the original '89 units because Chrysler so generously documented the operation of the software in the patents.

https://patents.google.com/patent/US4875391A/en <-- I highly recommend anyone interested in this project DL a copy of this patent at least.

Once the '89 is fully dis-assembled, it should be relatively easy to step up to the '91+ units that are flashable.

The SBEC flash module can also be installed into the '89/90 TCM to make it flashable over the SCI - exactly the same as an SBEC.




- - - Updated - - -

it's basically a step graph and sloped graph. pretty straight forward really. e.g. using the data in this table...

input to the table is in A. result comes back in B.

assumptions: starting coordinate is (0x00,0x00), last coordinate is (0xff,0xff)

00 <= A <= 0x29 b= (A - x0)/(x1 - x0) * (y1 - y0) + y0 = 0x00
29 < A <= 0x4E b= (A - x2)/(x3 - x2) * (y3 - y2) + y2 = value between 0x1c and 0x68
4E < A <= 0xFF b= (A - x4)/(x5 - x4) * (y5 - y4) + y4 = 0xff

so basically the graph points would be:
x y
0-(0x00,0x00)
1-(0x29,0x00)
2-(0x29,0x1c)
3-(0x43,0x68)
4-(0x43,0xFF)
5-(0xFF,0xFF)

i need to finish setting up mptune to be able to display this correctly.

Looks like that could be part of the shift map.



Eventually, I think we will need a way to correctly overlap the various tables that make up the complete shift map. How hard do you think that will be, Morris?

[wowzer]

posted up a new version of mptune that should be able to display the new table type. easier said then done. now if only someone with a long history of analyzing/detailing/understanding cals would actually determine what the code is doing....... hmm, who could do that ;-)

[wowzer]

shelgame. shouldn't be too hard. the program already can overlay graphs (e.g fuel tables/comparison tables etc) so the logic is there. would need to ADD some type of display table like we did with the calculated tables where we would add the related tables.

[olk93]

Hmmm very interesting the patent doc and as a side effect the "figures" with the shifting patterns/behaviour give a nice explanation why the tps-mod works

Look here and scroll down for Brad Davisons additions.
http://www.allpar.com/mopar/3up.html

[olk93]

Here for compare another patent published 1990 ... maybe we should try to collect all a604 related patents in a common place to ease the detective work ?
http://www.google.com/patents/US4938102

[Force Fed Mopar]

Depends on the year. The older units are factory flashable. But, I started dis-assembling the original '89 units because Chrysler so generously documented the operation of the software in the patents.

https://patents.google.com/patent/US4875391A/en <-- I highly recommend anyone interested in this project DL a copy of this patent at least.

Once the '89 is fully dis-assembled, it should be relatively easy to step up to the '91+ units that are flashable.

The SBEC flash module can also be installed into the '89/90 TCM to make it flashable over the SCI - exactly the same as an SBEC.

I was under the impression that the TCM had it's own diag plug. Or did the early ones have the engine diag plug connected to them?

[olk93]

My '91+'93LBs have a blue connector under the dashboard (near drivers left knee and it has for sure +-ccd
I am not sure if this connector has also rx/tx (SCI).
OTOH there has to be a sci connector somewhere in the car, no? - because how would the service guy flash/update a flashable-stock-tcm in the car?

[Aries_Turbo]

ooooh. progress.

i know its early, but has anyone seen anything that could lead to shift speed increase?

Brian

[olk93]

Brian what exactly do you mean...?
(english is not my native tongue)

[ShelGame]

Here for compare another patent published 1990 ... maybe we should try to collect all a604 related patents in a common place to ease the detective work ?
http://www.google.com/patents/US4938102

OK, here you go. Just go to patents.google.com and input these numbers. Enjoy

4875391
4887491
4905545
4928235
4935872
4936167
4938102
4939928
4944200
4947329
4951200
4951205
4965728
4965735
4968999
4969098
4975844
4975845
4982620
4986145
4991097
4993527
4998200
4998450
5014214
5115698
5148722
5168449
5211080
5235946
5278759
5458545
5459660
5584209
5680307

- - - Updated - - -

I was under the impression that the TCM had it's own diag plug. Or did the early ones have the engine diag plug connected to them?

Not sure.

The factory EATX flash adapter has it's own 60-way. So, the stock harness at least needs to be removed.
But, if the EATX has it's own SCI connector (I think it should), then an SBEC flash module installed into the EATX can be flashed over the SCI, just like an SBEC can.

[Aries_Turbo]

Brian what exactly do you mean...?
(english is not my native tongue)

the ultimate downfall of the 604/41TE in a high horsepower application is the slow speed of clutch engagement/disengagement during shifts when the trans controller is calibrated for factory specs (ie smooth, slow shifting) but the engine is making much more power.

the clutches slip alot then and the trans burns up.

in other words, lots of HP and slow shifts = ruined transmission.

i would think the primary overall goal of reverse engineering the TCU would be tuning the shift speed to be much faster so the trans would last under high boost/high torque in 1-3 gears.

does that make sense? if not i can take a different route to explain it.

Brian

[Force Fed Mopar]

Not sure.

The factory EATX flash adapter has it's own 60-way. So, the stock harness at least needs to be removed.
But, if the EATX has it's own SCI connector (I think it should), then an SBEC flash module installed into the EATX can be flashed over the SCI, just like an SBEC can.

Cool, yeah AFAIK the early 604 cars have a blue plug under the dash that is for the trans. So, would just have to make a plug that fit it to use a flash cable/module (it is different than the engine SCI plug). Not sure about the newer (96-up) cars, might be part of the OBD plug on them.

[wheming]

I thought the 6way blue plug was for the body harness diagnostic connector? I know i had plugged my drb2 into one before on some car.

[olk93]

I remember a service-guy having plugged in a drb2 (or3?) into the blue connector and he read the percentual wear of each "gear". I assume the communication drb <-> tcm was via ccd.

[Aries_Turbo]

he read the percentual wear of each "gear".

those are the adaptives that adjust shift timing to account for wear that i was talking about earlier.

the megasquirt based shift boxes and the TCM box that racerstev used dont have these functions.

when the wear numbers get to the point where the TCU cant adjust anymore electronically thats when you get limp in and other issues.

Brian

[ShelGame]

I remember a service-guy having plugged in a drb2 (or3?) into the blue connector and he read the percentual wear of each "gear". I assume the communication drb <-> tcm was via ccd.

That probably means that's a CCD Bus connector, not SCI...