lock AUDI A8 2001 D2 / 1.G 01V Transmission OBD Functions Workshop Manual

01-3

Security functions of the Transmission
Control Module (TCM)
When one or more components or sensors fail,
the Transmission Control Module (TCM) -J217-
activates the appropriate alternate functions or
emergency programs. This ensures destruction-
free operation of the automatic transmission with
some effect on the function and quality of
shifting.
When critical malfunctions occur with an active
TCM, the current selected gear will be held.
"Mechanical emergency running mode with the
control module active" is activated by the TCM as
soon as the driving situation regarding
transmission security and engine security permits
it.

Mechanical backup with active control
module

- The transmission shifts out of all forward gears
into hydraulic 4th gear. The torque converter
clutch is unlocked (not applied). All solenoid
valves are de-energized.

- Maximum shift pressure is applied to the power-
transmitting elements.

-
Reverse gear can be engaged. The shift lock
Pa
ge 4 of 13 On Board Dia
gnostic
(OBD
), function
11/20/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.AT02.01.1

01-4

- The Multi-function Indicator Light (MIL) lights up
after 2 driving cycles (Dcy); check DTC memory
( page 01
-43
and compare with DTC table
page 01
-45
).
If the TCM -J217- malfunctions (e.g. if the power
supply is faulty or the connector becomes
disconnected), the transmission will immediately
switch to "mechanical back-up mode with
inactive control module" and continue to
operate.

Mechanical backup with non-active control
module

- The transmission shifts out of all forward gears
into hydraulic 4th gear. The torque converter
clutch is unlocked (not applied). All solenoid
valves are de-energized.

- Maximum shift pressure is applied to the power-
transmitting elements.

- Reverse gear can be engaged. The shift lock
solenoid is active (in "P" and "N").

- All of the segments transmission range selector lever display are dark.
-
The MIL lights up when the Engine Control Module (ECM) has
recognized a CAN-bus malfunction (missing data exchange between
engine and transmission control modules) (after 2 Dcy); check DTC
Pa
ge 6 of 13 On Board Dia
gnostic
(OBD
), function
11/20/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.AT02.01.1

01-8

On Board Diagnostic (OBD), technical
data


Memory

Permanent memory
yes
Data output
Rapid data transfer
Blink code output yes
no
Output Diagnostic Test Mode yes
Basic setting no
Coding control module yes
Read measuring value block yes

Electrical/electronic component locations
Page 01
-11

Pa
ge 11 of 13 On Board Dia
gnostic
(OBD
), function
11/20/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.AT02.01.1

01-9
On Board Diagnostic II (OBD II), functions

Note:
The following modes can be selected via address word 33:
Mode
Function
1 Transmit diagnostic data:
Only certain individual test values can be read. Read the the measuring value block by using address word 02,
function 08.
2 Not applicable
3 Check DTC memory: Only emissions-influencing malfunctions are indicated immediately or after two driving cycles (Dcy), depending
on the malfunction, via the corresponding P-codes. Check DTC memory by using address word 02, function 02.
4 Erase DTC memory: DTC memory can be erased, even if it has not previously been read. Erase DTC memory by using address word
02, function 05.
5 Not applicable
6 Not applicable
7 OBD test results, continuously monitored: Emissions-related malfunctions can be read, even if these malfunctions have not existed long enough for the
MIL to be switched on.
Pa
ge 12 of 13 On Board Dia
gnostic
(OBD
), function
11/20/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.AT02.01.1