Volkswagen Workshop Service and Repair Manuals

Note:

Tank venting valve is closed when no current is supplied.

Checking activation:

=> Repair group 01; Final control diagnosis; Performing final control diagnosis

Special tools, workshop equipment, 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 1551/3A

Test conditions

• ● Fuse No. 1 must be OK.
• ● Coolant temperature must be at least 80 °C, =>display group 04, display zone 3.

Functional check

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select the engine control unit with the "Address word" 01. Connecting fault reader and selecting engine control unit:

=> Repair group 01; General to self-diagnosis; Connecting fault reader V.A.G 1551 and selecting engine control unit

• ‒ Press keys 0 and 4 for the function "Initiating basic settings" and confirm entry with Q key.

• ‒ Press keys 0, 7 and 0 for "Display group number 70" and confirm entry with Q key.

Note:

The engine must not be loaded during this diagnosis because the diagnosis will be interrupted and will not be started again until the engine is revved-up.

When the diagnosis is initiated by the engine control unit the display in display zone 4 jumps from "Test OFF" to "Test ON"

• ‒ Run engine at idling speed until the
       Specification "TVV OK"
  is displayed in display zone 4.

If the display indicates as described:

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

If the display does not indicate as described:

• ‒ Press ⇒key.
• ‒ Introduce final control diagnosis and activate tank venting valve (N80):

=> Repair group 01; Final control diagnosis; Performing final control diagnosis

• ‒ Interrogate fault memory:

=> Repair group 01; Fault memory; Interrogating and erasing fault memory of engine control unit