Ignition Control Unit (ICU)
- Remove connector from Ignition Control Unit (ICU) located above glove box or behind left kick panel and connect voltmeter to connector terminals No. 2 and 4. Turn ignition on. Voltage should read about 12 volts. If voltage is not present, repair open in terminal No. 2 (ground circuit) or open or short in circuit No. 15 (wire from positive side of ignition coil).
- Reconnect ICU connector. Disconnect coil wire from distributor cap center terminal and connect to ground using a jumper wire. Remove protective cover to gain access to rear of control unit connector.
- Connect digital voltmeter across rear of connector at terminals No. 3 and 6 of the control unit (4 and 6 on models with knock control unit, 2 and 6 on Volkswagen 16-valve). Turn ignition switch to "START" position. Voltage should be displayed while cranking engine. If NO voltage is displayed, see HALL EFFECT SENDING UNIT test.
- Turn ignition off. On Volkswagen 16-valve models, disconnect 15-wire connector of knock control unit. Disconnect 3-wire connector from distributor on all other models. Connect positive voltmeter lead to terminal No. 15 of coil. Connect negative voltmeter lead to terminal No. 1 of coil.
- Turn ignition on. Voltmeter should show voltage and must drop to zero volts within 1-2 seconds. If voltage does not drop, replace Hall control unit. If voltage drops, install short jumper lead to center terminal of distributor 3-wire connector (terminal No. 12 of knock control unit on Volkswagen 16-valve models). Lightly tap lead to ground. Voltage must rise to a minimum of 2 volts for a short time. If voltage rise is not indicated, replace Hall control unit.