Testing control unit power supply: Audi 2.0 (ABK, ADW)

ADW
The voltage for the Digifant control unit is supplied through the current supply relay for Digifant control unit -J176.

Note:

Fitting location of current supply relay for Digifant control unit -J176: On auxiliary relay carrier III in passenger footwell, contact position 1

Special tools, testers and auxiliary equipment required

Hand-held multimeter V.A.G 1526 or V.A.G 1526 A
Adapter set V.A.G 1594 A
Test box V.A.G 1598/18

Connect fault reader V.A.G 1551 and select engine electronics control unit => Page
01-2
.
Read measured value block 2
⇒
1
2
3
4
Read measured value block, display group 002 => Page
01-62
.
Test display in display zone 3.
Specification: approx. battery voltage

Press the ⇒key.

Rapid data transfer
HELP
Select function XX
Indicated on display:

Enter "06" for "End output" function and confirm entry with Q key.

If the specification is not obtained:

Carry out the following tests:

Testing power supply

With the ignition switched off, connect test box V.A.G 1598/18 to connector for engine control unit => Page
24-16
.

Set hand-held multimeter V.A.G 1526 to voltage measuring range (20 V direct current) and connect to contact 23 of the test box and to engine earth using test leads from V.A.G 1594 A.
Switch the ignition on.
Specification: approx. battery voltage

If the specification is not obtained:

Test the wiring between the plug connection of the Digifant control unit and the current supply relay -J176 according to the current flow diagram.

If the wiring is OK:

Test the voltage supply of the current supply relay -J176 => Page
28-33
.
Test the actuation of the current supply relay -J176 => Page
28-34
.
If the voltage supply as well as actuation of the current supply relay are OK, replace the current supply relay.

Testing earth supply

Test requirements:

Voltae supply at contact 23 OK => Page
28-30
.

Set hand held multimeter V.A.G 1526 to voltage measuring range (20 V direct current) and connect it as follows:

Test box V.A.G 1598/18 / socket · Specification
23 + 1 (earth) · approx. battery voltage
23 +42 (earth) · approx. battery voltage
23 +35 (earth) · approx. battery voltage

Switch the ignition on.

If the specified values are not obtained:

Test the wiring between the plug connection of the Digifant control unit and the earth points according to the current flow diagram.
Rectify open circuit, if necessary