Hall Sending Unit Test (With Knock Control Unit)

Perform Hall sending unit appropriateVOLTAGE SUPPLY CHECK . Turn ignition off. With 3-wire connector installed at distributor, move protective cover to gain access to rear of connector.
Connect voltmeter across terminals No. 1 and 2 at rear of 3-wire connector. Remove coil high voltage lead and ground with jumper wire.
Turn ignition switch to "START" position. Voltage should be indicated while starter is actuated.
If voltmeter does not show voltage reading while cranking, replace Hall sending unit. If voltmeter shows voltage while cranking, check for same voltage readings at Hall control unit terminals No. 4 and 6.
If readings are not identical, check wire harness from Hall sending unit to knock control unit and from knock control unit to Hall ignition control unit. See Fig 1.

Fig 1: Saab & Volkswagen & 7-Pin Ignition Control Unit Connector 15 Pin Knock Sensor Control Unit Connector

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Fig 2: Positioning Distributor for Hall Effect Testing

Courtesy of AUDI OF AMERICA, INC.

Fig 3: Audi Hall Sending Unit & 25-Pin Ignition Control Unit Connector

Courtesy of VOLKSWAGEN UNITED STATES, INC.