1999 AUDI A4 air condition

01-149


Output Diagnostic Test Mode
(DTM) (function 03)
Output Diagnostic Test Mode (DTM) is used to
check the function of actuators. Actuators are
also called actors. These are components that
the control module activates when it reacts to the
signals sent by sensors.
"Function of actuators" includes all functions and
properties of an actuator under operating
conditions. This means, for example:

- An electrically operated hydraulic valves that
opens and closes when activated by the control
module.

- The relay of an electrical motor when activated
by the control module. The motor switches on
and carry outs the task.
Before initiating the output Diagnostic Test Mode
(DTM), make sure there are no electrical
malfunctions in the system you wish to test. This
will enable you to recognize any mechanical
problems. Perform a guided troubleshooting
before starting output Diagnostic Test Mode
(DTM) page 01
-19
.
Are you sure there are no electrical malfunctions
in the system? If you have made sure that there
are no electrical malfunctions in the system, you
Pa
ge 1 of 66 Out
put Dia
gnostic Test Mode
(DTM
) (function 03
)
11/20/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU02.01.13

01-152

During the test, the individual test steps are
shown in the second line of the VAG1551
scan tool display. The following
abbreviations are used.
IV = Inlet valve
OV = Outlet valve
LF = Left Front
RF = Right Front
LR = Left Rear
RR = Right Rear
B+ = Battery Positive Voltage (B+) at valve
0V = 0 volts; No voltage at valve
Locked/free = Wheel condition; must be checked
by second technician
Hydr-P = Hydraulic pump
Pa
ge 5 of 66 Out
put Dia
gnostic Test Mode
(DTM
) (function 03
)
11/20/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU02.01.13

01-167


Note:
The operation manual for the VAS1978 wiring harness repair kit generally
forbids the repair of any lines in the ABS or related systems. This rule only
pertains to the shielded lines in these systems.
Multi-pin harness connector for ABS control module -J104- in proper
condition, with no bent, broken or corroded terminals. Replace any
damaged terminals using VAS1978 wiring repair kit. Ignition and electrical consumers switched off before beginning
testing (headlights, lighting, fan, etc.).
Pa
ge 21 of 66 Out
put Dia
gnostic Test Mode
(DTM
) (function 03
)
11/20/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.SU02.01.13