LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> BMW >> 2002 >> 745Li >> Repair and Diagnosis >> Electrical >> Charging Systems >> Generators & Regulators >> Testing >> Generator
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Generators & Regulators: Testing: Generator

  1. Check for correct corrections on charged battery, generator and starter motor. Make sure of good ground connection between engine and body. Make sure of good tension on ribbed V-belt.
  2. Read out DME/DDE fault memory.
  3. Connect diagnosis tester. Search down in the following menus:
    • FUNCTION SELECTION
    • COMPLETE VEHICLE
    • DRIVE
    • VOLTAGE AND CURRENT REGULATION
    • VOLTAGE AND CURRENT GENERATION
    Follow instructions in diagnostic program. To diagnose oscillograms for each fault, see GENERATOR OSCILLOGRAMS  . If generator is faulty, repair or replace it. To replace, see GENERATOR  under REMOVAL & INSTALLATION.
GENERATOR OSCILLOGRAMS

Fault Oscillogram
Fault-Free See Fig 1
One Phase Interrupted See Fig 2
Internal Fault See Fig 3
Open Circuit In Negative Diode See Fig 4
Short Circuit In Positive Diode See Fig 5
Open Circuit In Positive Diode See Fig 6
Open Circuit In Exciter Diode See Fig 7
Fig 1: Identifying Oscillogram For A Fault-Free Generator
G00301749Courtesy of BMW OF NORTH AMERICA, INC.
Fig 2: Identifying Oscillogram For One Phase Interrupted
G00301750Courtesy of BMW OF NORTH AMERICA, INC.
Fig 3: Identifying Oscillogram For Internal Fault
G00301751Courtesy of BMW OF NORTH AMERICA, INC.
Fig 4: Identifying Oscillogram For Open Circuit In Negative Diode
G00306585Courtesy of BMW OF NORTH AMERICA, INC.
Fig 5: Identifying Oscillogram For Short Circuit In Positive Diode
G00306586Courtesy of BMW OF NORTH AMERICA, INC.
Fig 6: Identifying Oscillogram For Open Circuit In Positive Diode
G00306587Courtesy of BMW OF NORTH AMERICA, INC.
Fig 7: Identifying Oscillogram For Open Circuit In Exciter Diode
G00306588Courtesy of BMW OF NORTH AMERICA, INC.
scientia non olet · About LEMON Manuals