Remove the plug from the output stage.
Connect the voltmeter to the terminals of the black/yellow and brown wires on the plug, turn on the ignition.
The voltage supply to the final stage is OK if the voltage is about 12V, otherwise you need to look for a wire break.
With the ignition off, connect the diode voltage tester with probes to the plug with the contact of the brown and green wires.
When the engine is cranked, the LED should blink, otherwise there is no signal from the Hall sensor.
Turn off the ignition, connect the plug to the output stage.
Remove the plug to the Hall sensor on the distributor.
Connect a voltmeter to the ignition coil between terminals 1/- and 15/+.
Turn on the ignition
On the three-pin plug that has been removed, connect the middle contact with a wire to ground for a while. Watch the voltmeter: the voltage drops to 2 V for a short time.
After this, the voltage drops to zero again.
If the voltage drops again, the control unit or output stage is faulty.
If the filling compound comes out, the ignition coil should also be replaced.
On engines with four valves per cylinder and the KE-Motronic system, next to the ignition coil (3) there is a final stage (2), from which the plug (1) is removed here.
[Material republished from the website AudiManual.ru]