OEM Bosch Voltage Regulator IB5881

Specifications

• MFR: BOSCH
• FEATURE 1: 100% New
• FEATURE 2: BSS (COM) Regulator
• FEATURE 3: COM ID Code: 31
• NOTE 1: Terminal Identification: Bss
• SPECS FOR: Bosch IR/IF Alternator
• SPECS: 12 Volt, B-Circuit, 10.6 - 16.0 Vset

Used On

• BMW (2006-2008)

Replaces

BMW: 12 31 7 540 657, 12 31 7 542 530, 7 540 657
Bosch: F 00M 145 317, F 00M 145 881, F 00M A45 222

Lester Numbers

11077

Unit Numbers

BMW: 12-31-4-487-081, 12-31-4-487-081, 12-31-7-542-529, 12-31-7-542-529, 12-31-7-543-083, 12-31-7-543-083, 7542529-03
Bosch: 0 124 525 083, 0 124 525 524
Original Reference Number: 302009RI, 89212506

Vehicle Application

BMW Car
323i L6 2.5L 2497cc 2006-2007
325i L6 3.0L 2996cc 2006
325xi L6 3.0L 2996cc 2006
550i V8 4.8L 4837cc 2006
650i V8 4.8L 4837cc 2006
750i V8 4.8L 4837cc 2006
750Li V8 4.8L 4837cc 2006
Z4 L6 3.0L 2996cc 2006-2008

BMW - Europe Car
242 3000, N52 B30 2005-2007
3 (E90) Eng.N52 B25 A 325 i 155kW N52 B25 A 2006-2008
3 (E90) Eng.N52 B25 A 325 i 160kW N52 B25 A 2005-2008
3 (E90) Eng.N52 B25 A 325 xi 160kW N52 B25 A 2005-2008
3 (E90) Eng.N52 B25 A, N52N B25 A 323 i 130kW N52 B25 A 2006-2011
3 (E90) Eng.N52 B30 A 330 i 190kW N52 B30 A 2005-2007
3 (E90) Eng.N52 B30 A 330 xi 190kW N52 B30 A 2005-2007
3 (E90) Eng.N52N B30 A 328 i 187kW N52N B30 A 2005-2007
3 Convertible (E93) Eng.N52 B25 A 325 i 160kW N52 B25 A 2007-2008
3 Coupe (E92) Eng.N52 B25 A, N52 B25 C 325 i 160kW 2005-2008
3 Coupe (E92) Eng.N52 B25 A, N52 B25 C 325 xi 160kW 2006-2008
3 Touring (E91) 323 i 140kW 2006-2008
3 Touring (E91) Eng.N52 B25 A, N52 B25 C 325 i 160kW 2004-2008
3 Touring (E91) Eng.N52 B25 A, N52 B25 C 325 xi 160kW 2005-2008
3 Touring (E91) Eng.N52 B30 A 330 i 190kW N52 B30 A 2005-2007
3 Touring (E91) Eng.N52 B30 A 330 xi 190kW N52 B30 A 2005-2007
3 Touring (E91) Eng.N52N B25 A 323 i 130kW 2006-2007
325 2500, N52 B25 2005-2007
5 (E60) Eng.N52 B25 A 525 i 160kW N52 B25 A 2004-2007
5 (E60) Eng.N52 B25 A 525 xi 160kW N52 B25 A 2005-2007
5 (E60) Eng.N52 B30 A 530 i 187kW N52 B30 A 2005-2010
5 (E60) Eng.N52 B30 A 530 i 190kW N52 B30 A 2004-2007
5 (E60) Eng.N52 B30 A 530 xi 190kW N52 B30 A 2004-2007
5 (E60) Eng.N52 B30 A, N53 B30 A 530 i 200kW 2007-2009
5 (E60) Eng.N52 B30 A, N53 B30 A 530 i xDrive 200kW 2007-2009
5 (E60) Eng.N52 B30 A, N53 B30 A 530 xi 200kW 2007
5 Touring (E61) Eng.N52 B25 A 525 i 160kW N52 B25 A 2004-2007
5 Touring (E61) Eng.N52 B25 A 525 xi 160kW N52 B25 A 2005-2007
5 Touring (E61) Eng.N52 B30 A 530 i 190kW N52 B30 A 2004-2007
5 Touring (E61) Eng.N52 B30 A 530 xi 190kW N52 B30 A 2005-2010
5 Touring (E61) Eng.N52 B30 A, N53 B30 A 525 xi 160kW 2007
5 Touring (E61) Eng.N52 B30 A, N53 B30 A 530 i 200kW 2007-2010
5 Touring (E61) Eng.N52 B30 A, N53 B30 A 530 i xDrive 200kW 2008-2010
5 Touring (E61) Eng.N52 B30 A, N53 B30 A 530 xi 200kW 2007-2010
6 (E63) Eng.N52 B30, N52 B30 A 630 i 190kW 2004-2007
6 Convertible (E64) Eng.N52 B30 A 630 i 190kW N52 B30 A 2004-2007
K15 3000, N52 B30 2005-2010
Savana 2500 2500, N52 B25 2005-2007
Stealth 3000, N52 B30 2005-2007
Vue 3000, N52 B30 2004-2007
Z4 3000, N52B30 2006-2010
Z4 (E85) Eng.N52 B25 A 2.5 i 130kW N52 B25 A 2006-2009
Z4 (E85) Eng.N52 B25 A 2.5 si 160kW N52 B25 A 2006-2009
Z4 (E85) Eng.N52 B30 A 3.0 si 195kW N52 B30 A 2006-2008
Z4 Coupe (E86) Eng.N52 B30 A 3.0 si 195kW N52 B30 A 2006-2009

Features & Benefits

• Genuine OEM replacement part
• Manufactured to original factory specifications
• Regulates alternator output voltage
• Helps maintain proper battery charging
• Supports stable charging system performance
• Original fit, function, and electrical characteristics
• Ideal for alternator rebuilding and repair
• Engineered for long-term reliability

What Does a Voltage Regulator Do?

The voltage regulator controls the alternator's output by regulating current supplied to the rotor field winding. As electrical demand changes, the regulator continuously adjusts field current to maintain the proper charging voltage for the battery and the vehicle's electrical system.

A properly functioning voltage regulator helps prevent battery overcharging and undercharging while protecting sensitive electrical components from excessive voltage. Because charging system performance depends on the interaction between the regulator, rotor, stator, rectifier, and battery, replacing a faulty regulator is an important step in restoring alternator performance.

Common Signs Replacement Is Needed

Replace the voltage regulator if you notice:

• Battery overcharging
• Battery not charging
• Low charging voltage
• High charging voltage
• Battery warning light illuminated
• Intermittent charging problems
• Headlights that brighten or dim with engine speed
• Charging system failure during testing
• Voltage regulator failure discovered during alternator rebuilding

Installation Recommendations

Installation should be performed by a qualified technician or experienced alternator rebuilder. Before installing the new regulator, inspect the brushes, brush holder, slip rings, rotor, stator, rectifier, wiring, and electrical connections for signs of wear or damage.

Always verify connector configuration and mounting style before installation. After assembly, bench-test the alternator to confirm proper charging voltage and overall charging system performance.

While You're Rebuilding

Inspect other common wear components to help maximize charging system reliability:

• Bearings
• Brushes
• Brush Holder
• Slip Rings
• Rectifier
• Diodes
• Rotor
• Clutch Pulley
• Insulators

Why Buy From RC Auto Electric?

RC Auto Electric specializes in genuine OEM and premium aftermarket alternator and starter rebuilding components for professional rebuilders, repair shops, automotive technicians, and DIY enthusiasts. Our extensive catalog includes thousands of electrical components backed by accurate cross-reference information to help simplify part identification and reduce ordering mistakes.

Disclaimer

Compatibility information is provided as a reference only. Manufacturing revisions, production changes, and previous rebuilding modifications may affect internal alternator components. Always compare the original OEM part number, connector configuration, mounting style, voltage specifications, cross-reference numbers, and product photographs before installation. If you are unsure about compatibility, contact RC Auto Electric before ordering.