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 Length Of Carbon Brushes

Courtesy of BMW OF NORTH AMERICA, INC.

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 For A Fault -Free Alternator

Courtesy of BMW OF NORTH AMERICA, INC.

Oscillogram for a faulty alternator:

One phase interrupted.

Repair/exchange alternator.

Fig 3: Identifying Oscillogram For One Phase Interrupted

Courtesy of BMW OF NORTH AMERICA, INC.

Interturn fault.

Repair/exchange alternator.

Fig 4: Identifying Oscillogram For Interturn Fault

Courtesy of BMW OF NORTH AMERICA, INC.

Open circuit in negative diode.

Repair/exchange alternator.

Fig 5: Identifying Oscillogram For Open Circuit In Negative Diode

Courtesy of BMW OF NORTH AMERICA, INC.

Short circuit in positive diode.

Repair/exchange alternator.

Fig 6: Identifying Oscillogram For Short Circuit In Positive Diode

Courtesy of BMW OF NORTH AMERICA, INC.

Open circuit in positive diode.

Repair/exchange alternator.

Fig 7: Identifying Oscillogram For Open Circuit In Positive Diode

Courtesy of BMW OF NORTH AMERICA, INC.

Open circuit in exciter diode.

Repair/exchange alternator.

Fig 8: Identifying Oscillogram For Open Circuit In Exciter Diode

Courtesy of BMW OF NORTH AMERICA, INC.