Volkswagen Workshop Service and Repair Manuals

Special tools, testers, measuring instruments and auxiliary items required

• ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
• ◆ Test box V.A.G 1598/18
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Check conditions

• ● Battery voltage at least 11 V.
• ● Alternator must be OK

Test sequence

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control unit. When doing this the engine must be running at idling speed.
  (Connecting fault reader and selecting engine control unit .)

• ‒ Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

• ‒ Press keys 0, 0 and 2 for "Display group number 2" and confirm entry with Q key.

• ‒ Read off display values in display zone 3.
       Specification: constantly approx. battery voltage
• ‒ Press ⇒key.

• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

If the displayed figure fluctuates or the battery voltage is not attained:

• ‒ Switch off ignition.
• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.

• ‒ Measure supply voltage between test box sockets 1+21 using multimeter and adapter cables from V.A.G 1594:
       Specification: at least 11 V
• ‒ Switch on ignition.
• ‒ Measure supply voltage between test box sockets 1+23 using multimeter and adapter cables from V.A.G 1594:
       Specification: at least 11 V

If the specifications are not attained:

• ‒ Check wiring connections according to relay plate according to current flow diagram.