12 31 009 Checking alternator and regulator switch

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2008 MINI Cooper, 2007 MINI Cooper, 2006 MINI Cooper, 2005 MINI Cooper, and 2004 MINI Cooper. However, it is still accessible from the selected car via links, so may be relevant.

Test Requirements:

Correct connections on charged battery.
Correct connections on alternator and starter motor.
Good ground connection between engine and body.
Tightened drive belt.

Connect DIS Tester.

Measurement.
Checking alternator.

If charge indicator lamp is permanently lit:

Remove voltage regulator and check carbon brushes, replace if necessary.

Replace alternator regulator switch.

NOTE: Minimum length of carbon brushes "A" = 5 mm.

Fig 1: Identifying Minimum Length Of Carbon Brushes

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If charge indicator lamp goes out while engine is running:

Check control voltage.

Regulator switch must be replaced if control voltage is not achieved.

Replace alternator regulator switch.

From E46/E39 With Multifunction Regulator.

Recognizable by plug connection on regulator.

Connect DIS Tester.

Function selection.
Complete vehicle.
Drive.
Voltage and current regulation.
Voltage and current generation.
Work through test modules.

Oscillogram For A Fault-Free Alternator:

Fig 2: Identifying Oscillogram Waveform (Fault-Free Alternator)

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Oscillogram For A Faulty Alternator:

One phase interrupted.

Repair/exchange alternator.

Fig 3: Identifying Oscillogram Waveform (One Phase Interrupted)

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Interturn fault.

Repair/exchange alternator.

Fig 4: Identifying Oscillogram Waveform (Interturn Fault)

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Open circuit in negative diode.

Repair/exchange alternator.

Fig 5: Identifying Oscillogram Waveform (Open Circuit In Negative Diode)

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Short circuit in positive diode.

Repair/exchange alternator.

Fig 6: Identifying Oscillogram Waveform (Short Circuit In Positive Diode)

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Open circuit in positive diode.

Repair/exchange alternator.

Fig 7: Identifying Oscillogram Waveform (Open Circuit In Positive Diode)

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Open circuit in exciter diode.

Repair/exchange alternator.

Fig 8: Identifying Oscillogram Waveform (Open Circuit In Exciter Diode)

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