What Does Recoding Do?
U.S. specification A8's come with transmission coding suitable for a very
leisurely driving style. It upshifts early and does not support "spirited
driving" like most A8 owners would like to see.
One thing it does not do good is matching engine power and RPM's to the
driver's need. When the driver wants to pass or accelerate requiring 40 or 50
additional HP, the transmission does not cooperate. If it did, it would drop
one or two gears immediately with a slight depression of the gas pedal.
Instead, the transmission stays in gear, and adequate power is not transferred
as the driver needs or wants. The driver then depresses the gas pedal further,
and finally the transmission downshifts two or three gears and close to 300 HP
is applied to the drivetrain.
This lurches the car forward and does not result in what the driver wants; a
slight increase in power, in a controlled manner. This surge of power after
downshifting two or three gears can cause the car balance to be upset, and if
the power is needed to avoid a potential hazard, the transmission is too slow
in responding.
By recoding the transmission to the sport mode settings outlined below, the car
becomes much more smooth when requesting additional power. The following
explains how the TCU controls these shift points and the different software
codes already built into all A8's.
The transmission control unit (TCU) controls the transmission by adjusting two
position and proportional (throttling) solenoids in the transmission. These
solenoids determine gear position, torque converter settings (open, locked and
throttling), kick down, etc.
The TCU "learns" the driving style of the driver by summing the way the gas
pedal is pushed, i.e. how hard the car is driven. It then develops a dynamic
shift program (DSP) index number from 0-256. This is display group 12 under
transmission. It has the following four display fields:
How car is driven, load (flat ground - no load "E", hill - load "B")
Dynamic index number (is calculated using driving resistance index and driver
evaluation) 0-256
Driving resistance index (is used to calculate dynamic identification number)
0-256
Driver evaluation (Is used to calculate dynamic identification number) 0-256
The following table is from the Bently manual. These measuring blocks can be
monitored in display group 12 in the transmission module using the ross-tech
software.
The dynamic index number controls how the transmission shifts. If your A8 has
the stock transmission coding of 00002, then it sums dynamic index number
closer to "old man mode" versus "sport mode".
There are built in software coding that came from the factory that will allow
you to shift the software to "sport mode". It differs for the 97 without
tiptronic, the 98 and 99 with tiptronic, and the 00 and later with tiptronic.
The following explains each.
Transmission Coding for 1997 to 1999 A8's
2000 and later A8's have additional codes explained below.
97 without Tiptronic
If your car does not have tiptronic, it won't hold first gear with the "sport"
setting (00011 or 00012). From the factory it came with the coding of 00002,
which is the stock setting for U.S. and Canada. 00001 is for the rest of the
world. It appears that there is little to no difference between the two "DSP
on" settings.
If the transmission is recoded to 00012 (DSP shut off U.S. and Canada), you
will find that the transmission holds gears slightly longer, and learns quicker
than with the stock coding. It is a slight improvement over the 00002 coding.
It will also take code 00011 (DSP shut off rest of the world). This coding
makes the car more of a "European touring machine". It really makes a huge
difference in the way the engine and transmission responds. It will shift at
higher RPM's and downshift with much less throttle input that the 00002 or
00012 code. The transmission matches the engine speed to the driver's needs,
where with the 00002 and 00012 code, the engine speed is too slow for the
driver's needs.
98 and 99 with Tiptronic
There are two ways the 98 can be recoded to sport. If recoded to 00012, it acts
just like the 97 recode above, with just slightly higher shift points than
stock and it learns faster. However, it will not hold first gear to redline in
tiptronic unless the driver starts from a stand still and holds the gas pedal
to floor. Doesn't solve most aggressive driver's problems.
If coded to 00011, it acts much differently. The following are characteristics
of the 00011 code:
Holds 1st gear in tiptronic, upshifts to 2nd when it hits redline or when the driver shifts
Can downshift to 1st, as long as it doesn't mean hitting rev limiter
Shifts to higher gear in tiptronic when redline is reached
Shifting appears to be slightly faster in tiptronic mode
Adaptive shift pattern works very well, shifts to more sporty mode after a
short while of inspired driving and vice versa
Kicks down in tiptronic in certain situations when the gas pedal is floored
Downshifts to hold speed downhill when using cruise control
This is very different than the 00012 coding. Remember, once you have the
ross-tech software, you can always change it from one to another!
00 and later with Tiptronic
The 00's and later have different options than the 99's and earlier. They can
be coded as followed:
00002, stock coding
00012, sport coding
00022, stock coding, but will hold first gear in Tiptronic to redline
regardless of throttle position and then shift to second.
00032, sport coding and will hold first gear in Tiptronic to redline regardless
of throttle position and then shift to second.
2002 A8L
The 2002 A8L (from at least one source) came from the factory with transmission coding of 00002. The owner recoded it to 00032, reported as better, but it still did not shift as soon as they would like.
After the car was returned from the Audi dealer after the first service, it was coded as 01002. The owner then recoded it to 01032. The car holds 1st gear to redline and shifts to second.
This coding is very similiar to the S8 coding from the factory.
If you have a S8 and can determine what stock coding is, please
email me
and report your results. I will update this page.
How to Recode
First, you will need the
ross-tech software. It's $200 for the cable and software license. Once you have it, follow these
instructions.
Open software and connect to the car.
Turn the ignition on, but leave engine off. The transmission cannot be recoded
with the engine running.
See
Main Screen, and click on Select Control Module: Select.
See
Recode dialog, where you can enter new numbers for transmission software coding (and
workshop code). Select "Do it". More information on the codes can be
found here.
