Volkswagen Workshop Service and Repair Manuals

Only engine code AFT

Test conditions

• ● Activation OK. , Final control diagnosis

Checking voltage supply

• ‒ → Pull 2 pin connector -1- off valve -2-.
• ‒ Connect multimeter to valve to measure resistance.
       Specification: 25...35 ω

If the specification is not obtained:

• ‒ Replace intake manifold change-over valve.

Checking function

• ‒ Start engine and run at idling speed.
• ‒ → Rev. up to 4000 rpm,
       the vacuum unit -arrow- must switch over.

If the vacuum unit does not switch over:

• ‒ Check vacuum hose/pipe to vacuum unit and vacuum unit.
• ‒ Check at lever if shaft is free to move.

If the following conditions are fulfilled:

• ● Activation (final control diagnosis) OK.
• ● Vacuum hose/pipe and vacuum unit OK.
• ● Shaft free to move

• ‒ Renew intake manifold change-over valve (N156) , item 5 .