Output Diagnostic Test Mode (DTM) (Function 03)
Output Diagnostic Test Mode (DTM) (function 03)
Function
Output DTM allows functional checking of A/C control head actuated components (DTM components). Actuators receive output signals generated by the control head via VAG1551 Scan Tool (ST) in sequence. Function is confirmed in accordance with specified responses.
The following components are tested in sequence using Output DTM:
1 - A/C Clutch -N25-
2 - Fresh Air Blower -V2-
3 - Coolant Fan -V7-
4 - Fresh Air/Recirculating Flap Two-Way Valve -N63- 1)
5 - Temperature Regulator Flap Motor -V68-
6 - Central Air Flap Motor -V70-
7 - Footwell/Defroster Flap Motor -V85-
8 - Air Flow Flap Motor -V71-
9 - Interior Temperature Sensor Fan -V42-
10 - A/C control head display segment test
11 - Outside Air Temperature Display -G106- test
1) Not installed on m.y. 1997 vehicles.
NOTE:
- During Output DTM on vehicles with Control Head (E87) Part Number 8D0 820 043 D, A/C Compressor Clutch (N25) DTC "01270, mechanical malfunction SP" may be stored even though no malfunction is present. Corrective action: When output DTM is complete, check DTC memory. If above DTC is present, erase DTC memory.
- When starting Output DTM, temperature and air distribution flap flap motors move to predetermined positions in preparation for individual tests: Temperature Regulator Flap Motor V68: moves to "heat" position. Central Air Flap Motor -V70- moves to "floor & defroster outlet" position. Footwell Defroster Flap Motor V85 moves to "defrost" position.
- Output DTM can be repeated several times, if necessary.
- During Output DTM, vehicle must not be moved and engine speed must be less than 3000 rpm.
- During Output DTM, A/C system control is switched off and all segments in both A/C control head displays are actuated.
- Interior temperature sensor fan -V42- is activated via an A/C control head:
with one display after activation of the coolant fan.
with two displays after activation of air flow flap motor.
- Outside air temperature display -G106- is activated via an A/C control head
with one display after activation of air flow flap motor.
with two displays after activation of idle regulation.
- For the A/C control head -E87-, the instrument panel interior temperature sensor -G56- is installed with only one display in the -E87-, -V42- and -G56- are not individually replaceable. If -E87- is malfunctioning, they must be replaced together.
- A/C control heads with one display indicate that output diagnostic test mode is completed after activation of the last component ("END" is indicated on the Scan Tool display).
Starting output Diagnostic Test Mode (DTM)
- Start engine, switch on compressor (press "Auto" button), adjust air flow to center instrument panel outlets only.
- Connect Scan Tool VAG1551 or 1552 in operating mode -1-, enter address word 08 "A/C Heating Electronics" and move forward in program until "select function XX" appears in the display.
- Switch on printer by pressing the PRINT button (indicator lamp in button comes on).
- Check DTC memory With Manufacturer's Scan Tool
- Note any stored DTCs for reference and move forward in program until "select function XX" appears in the display.
Indicated on display (function selection)
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -3-.
Indicated on display
Rapid data transfer Q
03 - Output Diagnostic Test Mode
- Press -Q- button to confirm input.
Indicated on display
Output Diagnostic Test Mode
A/C clutch - N25
- Advance through all DTM component checks using -> button.
- Refer to output DTM table to confirm function of DTM components and test results.
NOTE:
- If a DTM component fails to respond as specified, perform all corrective actions, checks and tests recommended in output DTM table.
- A/C system component locations: engine compartment (note specific model year information).
- A/C system component locations: passenger compartment (note specific model year information).
- Output DTM can be ended by pressing the -C- button.
- After ending output DTM, check DTC memory.
- If the readout "function unknown or cannot be carded out at the moment" appears in the display at the start of output DTM, e.g. when engine not running, press -> button and once again select "function 03 Output Diagnosis Test Mode (DTM)" (DTM component "A/C Clutch N25" is no longer actuated for this test).
- If the readout "function unknown or cannot be carried out at the moment" appears in the display, Read measuring value block (display group 1). Read Measuring Value Block Tables
Indicated on display
Function is unknown or cannot
be carried out at the moment!
- If this readout appears in the display, output Diagnostic Test Mode (DTM) is ended.
- VAG1551 Scan Tool (ST) can be returned to the function mode by pressing the button.
Output Diagnostic Test Mode (DTM) table
