Volkswagen Workshop Service and Repair Manuals

• ● Hall sender OK.
• ● Electrical check, Test step 16 OK, checking
  =>Page 01-20
• ● Ignition transformer OK.

Checking voltage supply

• ‒ Pull 3 pin plug off ignition transformer.

• ‒ → Connect hand multimeter V.A.G 1526 to measure voltage with aux. cables from V.A.G 1594 to the contacts 1 and 3 of the disconnected plug.
• ‒ Switch on ignition.
       Specification: Approx. battery voltage
• ‒ Switch off ignition.

Checking activation

• ‒ Disconnect plug for injector and intake air preheating sender from the injection unit.

• ‒ → Connect diode test lamp V.A.G 1527 with aux. cables from V.A.G 1594 and adapters V.A.G 1594/15 to contacts 2 and 3 of the plug.
• ‒ Operate starter and check ignition signal from Mono-Motronic control unit.
       LED must flicker

The LED does not flicker:

• ‒ Renew Mono-Motronic control unit (J257).
• ‒ Connect 3 pin plug and H.T. cable to ignition transformer.

• ‒ → Connect diode test lamp with aux. cables and clamps to the contacts 1 and 15 on ignition transformer.

• ‒ Operate starter.
       The LED must flicker,
  if necessary renew output stage.