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Transmission Control Module (TCM) soft coding experiment. I did not remove the thunk but :-) ...
04-14-2002, 01:39 PM
#1
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Transmission Control Module (TCM) soft coding experiment. I did not remove the thunk but :-) ...
<b><i>*** WARNING/DISCLAIMER *** </i>- Coding your Transmission Control Module outside of documented values may have undesireable effects. Coding of your Transmission Control Module is done enitrely at your own risk.</b>
I performed a little experiment this afternoon as I promised I would do in <a href="https://forums.audiworld.com/a6/msgs/141210.phtml"> a previous post</a>. My car is a 2001 A6 2.7T with the 5-speed Automatic transmission.
The original coding was "00002". I changed it to "00022". This value <u><b>is not</b></u> documented in the Bentley manual.
Unfortuneately the <b>thunk still remains</b>... I did not get the "slam", but I can't always reproduce the slam so I can't say for sure if it has been removed.
The reason I tried the values that I did was from a post on the <a href="http://groups.yahoo.com/group/VAG-COM/message/6156">VAG-COM e-group</a> a while ago. Since the value was from a totally different car (Passat) with a totally different transmission I did not know what to expect. I took the risk anyhow and luckily for me the coding was not a secret "self-destruct" code ;-).
This is what I observed:
<u>(D - mode)</u>
- transmission still upshifts through the higher gears as normal.
- transmission still automatically downshifts through the gears as you slow to a stop.
- dynamic shift programming (as visualized in measuring block 12) was no different than observed with stock coding.
- car would downshift when accel. was floored.
<u>(Tip - mode)</u>
- <b>transmission will stay in 1st gear all the way to redline</b> (with only mild accel. pedal pressure). In normal coding the car will shift to second around 2K RPM unless you absolutely stuff the accel. pedal.
- transmission will shift from 1st to 2nd if you let off the accel. pedal even a tiny bit. As stated above, it will stay in 1st all the way to redline and then shift to 2nd.
- transmission automatically downshifts through the gears as you slow to a stop.
- manual upshift/downshift behaves normally.
- you still <b>cannot downshift to 1st if your speed is above 10km/hr.</b> A good safety feature in my mind.
- car would downshift when accel. was floored.
/dan
I performed a little experiment this afternoon as I promised I would do in <a href="https://forums.audiworld.com/a6/msgs/141210.phtml"> a previous post</a>. My car is a 2001 A6 2.7T with the 5-speed Automatic transmission.
The original coding was "00002". I changed it to "00022". This value <u><b>is not</b></u> documented in the Bentley manual.
Unfortuneately the <b>thunk still remains</b>... I did not get the "slam", but I can't always reproduce the slam so I can't say for sure if it has been removed.
The reason I tried the values that I did was from a post on the <a href="http://groups.yahoo.com/group/VAG-COM/message/6156">VAG-COM e-group</a> a while ago. Since the value was from a totally different car (Passat) with a totally different transmission I did not know what to expect. I took the risk anyhow and luckily for me the coding was not a secret "self-destruct" code ;-).
This is what I observed:
<u>(D - mode)</u>
- transmission still upshifts through the higher gears as normal.
- transmission still automatically downshifts through the gears as you slow to a stop.
- dynamic shift programming (as visualized in measuring block 12) was no different than observed with stock coding.
- car would downshift when accel. was floored.
<u>(Tip - mode)</u>
- <b>transmission will stay in 1st gear all the way to redline</b> (with only mild accel. pedal pressure). In normal coding the car will shift to second around 2K RPM unless you absolutely stuff the accel. pedal.
- transmission will shift from 1st to 2nd if you let off the accel. pedal even a tiny bit. As stated above, it will stay in 1st all the way to redline and then shift to 2nd.
- transmission automatically downshifts through the gears as you slow to a stop.
- manual upshift/downshift behaves normally.
- you still <b>cannot downshift to 1st if your speed is above 10km/hr.</b> A good safety feature in my mind.
- car would downshift when accel. was floored.
/dan
04-14-2002, 02:53 PM
#2
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Cool!!!
But this is not a thing I would attempt on my car, I'm to affraid that my dealer discover it and it would probably void my waranty!!! But it is very cool.
04-14-2002, 04:23 PM
#3
AudiWorld Senior Member
Thread Starter
Results of further experimentation...(secret sport mode!?)
<b>*** WARNING/DISCLAIMER *** - Coding your Transmission Control Module outside of documented values may have undesireable effects. Coding of your Transmission Control Module is done enitrely at your own risk.</b>
I tried some additional TCM coding values:
"00000" - the original coded value remained after the recoding attempt. The Bentley manual describes this as an invalid value. Cool, as expected.
"00001" - the original coded value remained after the recoding attempt. Hmmm, the Bentley says this is a correct value for "Rest of World" <b>but the TCM would not accept the code</b>.
"00012" - Hmmm, another undocumented value was accepted. Read on!
First, with "00012" code, I should report that the transmission seemed to behave just like it did with stock coding value. The transmission seemed to shift normally and the 1st to 2nd shift behaviour was just like stock. All <i>easily to determine</i> behaviours seem to be the same as "stock" coding.
But, I did notice the following differences while doing data logging with VAG-COM. The differences showed up in measuring block 12.
Here are the details of measuring block 12 of the TCM.
<img src="http://home.ix.netcom.com/~drhaller/Audi/TCM_MeasuringBlock12.jpg">
I conjecture that it is display fields 2 and 4 in block 12 of the TCM that determine "past experience" and "current driver demand". I also conjecture that these numbers are what is used to determine the shift profile.
Before my experimentation it was my understanding that the "drivers" characteristics were "remembered" in the TCM across engine starts (this seems to be false). The Tiptronic transmission is marketed as able to select a shift program based on past driving style and current demands from a huge array of choices.
Now to the good stuff! Observations were made in "D" mode.
<u>My observations with "00002" (stock) or "00022" coded.</u>
- Display fields 2 thru 4 start at zero on engine restart.
- Display field 2 increases as driving gets more agressive. Seems to be a long term average of how "sporty" you drive. This number will go down (over time) if you start driving more relaxed.
- Display field 3 was always 0.
- Display field 3 seems to be a more near term "current" indication of how "sporty" you are driving. This number is constantly fluctuating.
<u>My observations with "00012" coded.</u>
- Display field 2 started at 50 when I started the car. <b>Is this the undocumented sport mode that 2002 cars get?</b>
- Display fields 3 and 4 start at zero on engine restart (same as observed with stock coding).
- Display field 2 increases as driving gets more agressive. <b>Never went below 50 during my experiment</b>. Seems to be a long term average of how "sporty" you drive. This number will go down (over time) if you start driving more relaxed.
- Display field 3 was always 0 (same as observed with stock coding).
- Display field 3 seems to be a more near term indication of how "sporty" you are driving. This number is constantly fluctuating (same as observed with stock coding).
/dan
I tried some additional TCM coding values:
"00000" - the original coded value remained after the recoding attempt. The Bentley manual describes this as an invalid value. Cool, as expected.
"00001" - the original coded value remained after the recoding attempt. Hmmm, the Bentley says this is a correct value for "Rest of World" <b>but the TCM would not accept the code</b>.
"00012" - Hmmm, another undocumented value was accepted. Read on!
First, with "00012" code, I should report that the transmission seemed to behave just like it did with stock coding value. The transmission seemed to shift normally and the 1st to 2nd shift behaviour was just like stock. All <i>easily to determine</i> behaviours seem to be the same as "stock" coding.
But, I did notice the following differences while doing data logging with VAG-COM. The differences showed up in measuring block 12.
Here are the details of measuring block 12 of the TCM.
<img src="http://home.ix.netcom.com/~drhaller/Audi/TCM_MeasuringBlock12.jpg">
I conjecture that it is display fields 2 and 4 in block 12 of the TCM that determine "past experience" and "current driver demand". I also conjecture that these numbers are what is used to determine the shift profile.
Before my experimentation it was my understanding that the "drivers" characteristics were "remembered" in the TCM across engine starts (this seems to be false). The Tiptronic transmission is marketed as able to select a shift program based on past driving style and current demands from a huge array of choices.
Now to the good stuff! Observations were made in "D" mode.
<u>My observations with "00002" (stock) or "00022" coded.</u>
- Display fields 2 thru 4 start at zero on engine restart.
- Display field 2 increases as driving gets more agressive. Seems to be a long term average of how "sporty" you drive. This number will go down (over time) if you start driving more relaxed.
- Display field 3 was always 0.
- Display field 3 seems to be a more near term "current" indication of how "sporty" you are driving. This number is constantly fluctuating.
<u>My observations with "00012" coded.</u>
- Display field 2 started at 50 when I started the car. <b>Is this the undocumented sport mode that 2002 cars get?</b>
- Display fields 3 and 4 start at zero on engine restart (same as observed with stock coding).
- Display field 2 increases as driving gets more agressive. <b>Never went below 50 during my experiment</b>. Seems to be a long term average of how "sporty" you drive. This number will go down (over time) if you start driving more relaxed.
- Display field 3 was always 0 (same as observed with stock coding).
- Display field 3 seems to be a more near term indication of how "sporty" you are driving. This number is constantly fluctuating (same as observed with stock coding).
/dan
04-14-2002, 06:29 PM
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You don't say, so I presume this was in "D" rather than "Tip" mode?
Either way, it probably shouldn't affect the behavior when the car is in Tip mode, since you are (more or less) in full control.
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04-14-2002, 06:39 PM
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It is possible to drop from 2nd to 1st above 10km/hr...
If you tip it down and simultanously floor the accelerator it will drop from 2nd to 1st. This is with the stock programming on the 2001 2.7T.
04-14-2002, 07:17 PM
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Strange, I have 2 2000 A6s in my family and they both
operate differently. The one will stay in first gear until redline any time I am in Tip mode, and will let me downshift at any speed into first. I had the car into the dealer and they are puzzled. The other A6 automatically shifts into second if you lift off the trottle and will not let me downshift until I am below 10 mph.
I wish I had the ability to control first in my S4 the way I do on my A6.
I wish I had the ability to control first in my S4 the way I do on my A6.