Ignition Control Unit (Vanagon)

Turn ignition off. Attach DVOM to ignition coil primary terminals. Disconnect Hall Effect sender wire harness connector from distributor. See Fig 1 . Turn ignition on.
While observing DVOM reading, attach center terminal of connector to ground for 3 seconds. Voltage reading should briefly increase to 4.5 volts. If voltage reading did not increase, check wiring for short or open circuit. If wiring is okay, replace ignition control unit.

Fig 1: Locating AFC-Digifant Components (Vanagon)

Courtesy of VOLKSWAGEN UNITED STATES, INC.

NOTE: Knock control is integral in AFC-Digifant ECU.