Checking the voltage regulator (Audi A4 B6)

1. Connect the multimeter between the positive terminal (red wire) generator and ground.

2. To warm up the generator to operating temperature (about 80°C), the engine must rotate at a speed of 3000 to 4000 rpm for two minutes. During starting, the voltage (at an outside temperature of 20°C) may drop to 8 volts.

3. Turn on the parking light, radio or fresh air blower. This corresponds to a current consumption of 3 to 7 Amps. If the regulated voltage is now 13.5 to 14.8 Volts, then the generator and regulator are working properly. In order for the battery to be charged while the vehicle is in use, the generator voltage (on-board network voltage) there must be more battery voltage.

4. Turn on the high beam and repeat the measurement at an engine speed of 3000 rpm. The voltage may exceed the previously measured value by no more than 0.4 V.

5. If the measurement shows higher voltages, the regulator is faulty and needs to be replaced. If the voltage is too low, this indicates wear of the contact carbons. In this case, dismantle the generator and take it to an electrical workshop for overhaul (see also the section describing how to check and replace contact carbons).

[This article was copied from the website: AudiManual.ru]