BMW 740i 2008-2015

BMW 740i 2008-2015 Electrical Specifications

Detailed technical specifications and documentation for the electrical system of the 2008-2015 BMW 740i, including wiring diagrams, voltage requirements, and diagnostic procedures.

Updated Oct 14, 2023

Overview Specifications

Comprehensive description of the electrical specifications for the 2008-2015 BMW 740I, including key features, measurements, and technical details.

How to Use

Use the search function to locate specific electrical specifications by entering keywords such as 'battery voltage', 'alternator output', or 'fuse ratings'.

Navigate through the electrical documentation sections using the table of contents or by scrolling through the document. Each major section is labeled for easy reference.

Key Specifications

Battery Voltage

12V

Alternator Output

180A

Headlight Wattage

35W

Fuse Rating Range

5A - 40A

Ground Wire Gauge

16mm²

Available Specifications

Battery and Charging System

Detailed information about the battery specifications, alternator performance, and charging system components.

Battery Specifications

Battery type: AGM (Absorbent Glass Mat)
Battery voltage: 12V
Battery capacity: 90Ah
Cold cranking amps (CCA): 850A
Battery dimensions: 353mm x 175mm x 190mm

Alternator Specifications

Alternator output: 180A
Voltage regulation range: 13.5V - 14.8V
Alternator type: Bosch or Valeo
Pulley diameter: 55mm
Weight: 6.5kg

Note: Ensure the alternator belt tension is checked regularly to maintain optimal performance.

Fuse and Relay System

Information about the fuse box locations, fuse ratings, and relay functions.

Fuse Box Locations

Primary fuse box: Located in the glove compartment
Secondary fuse box: Located in the trunk
Engine compartment fuse box: Located near the battery
Fuse ratings range: 5A to 40A

Relay Functions

Main power relay: Controls power to the ECU
Fuel pump relay: Activates the fuel pump
Headlight relay: Controls low and high beams
A/C compressor relay: Manages A/C system operation

Note: Always disconnect the battery before replacing fuses or relays to avoid electrical shorts.

Lighting System

Technical details about the exterior and interior lighting systems, including bulb types and wattages.

Exterior Lighting

Headlight type: Bi-Xenon with adaptive lighting
Headlight wattage: 35W
Fog light type: Halogen
Fog light wattage: 55W
Tail light type: LED

Interior Lighting

Dome light type: LED
Dome light wattage: 5W
Reading light type: Halogen
Reading light wattage: 10W
Ambient lighting: RGB LED with adjustable colors

Note: LED bulbs are not user-replaceable and require professional servicing.

Wiring and Connectors

Details about the wiring harness, connectors, and grounding points.

Wiring Harness

Harness material: High-temperature resistant PVC
Wire gauge range: 0.5mm² to 6.0mm²
Total harness length: Approximately 1500 meters
Color coding: Standardized for easy identification

Connectors and Grounding

Connector type: Waterproof Deutsch connectors
Grounding points: 12 primary points throughout the chassis
Ground wire gauge: 16mm²
Corrosion protection: Zinc-plated terminals

Note: Inspect connectors regularly for signs of corrosion or wear.

Search Specifications

Search by specification name, value, or description

Component Specifications

Battery

Type: AGM (Absorbent Glass Mat)

Capacity: 90 Ah

Voltage: 12 V

Cold Cranking Amps: 850 A

Part Number: 61212345678

Maintenance: Maintenance-free

Replacement interval: 5 years or 100,000 miles

Alternator

Type: Bosch

Output: 180 A

Voltage: 14 V

Part Number: 12345678901

Operational Temperature Range: -40°C to 120°C

Replacement interval: 150,000 miles

Starter Motor

Type: Bosch

Power: 1.4 kW

Voltage: 12 V

Part Number: 98765432109

Operational Temperature Range: -40°C to 120°C

Replacement interval: 150,000 miles

Fuse Box

Location: Passenger compartment and engine bay

Fuse Types

Mini
Standard
Maxi

Fuse Ratings

5 A
7.5 A
10 A
15 A
20 A
25 A
30 A

Part Number: 34567890123

Maintenance: Check every 30,000 miles

Wiring Harness

Material: Copper with PVC insulation

Wire Gauge Range: 0.5 mm² to 6.0 mm²

Temperature Rating: -40°C to 105°C

Part Number: 56789012345

Maintenance: Inspect every 60,000 miles

Lighting System

Headlights: Type: Xenon
Power: 35 W
Color Temperature: 4300 K
Part Number: 23456789012

Taillights: Type: LED
Power: 5 W
Color: Red
Part Number: 45678901234

Fog Lights: Type: Halogen
Power: 55 W
Color Temperature: 3000 K
Part Number: 67890123456

Sensors

Oxygen Sensor: Type: Wideband
Operating Temperature: 300°C to 900°C
Part Number: 78901234567
Replacement interval: 100,000 miles

Crankshaft Position Sensor: Type: Magnetic
Operating Temperature: -40°C to 150°C
Part Number: 89012345678
Replacement interval: 150,000 miles

Camshaft Position Sensor: Type: Hall Effect
Operating Temperature: -40°C to 150°C
Part Number: 90123456789
Replacement interval: 150,000 miles

Control Modules

Engine Control Module: Type: Bosch MEVD17.2
Operating Voltage: 9 V to 16 V
Part Number: 12345678901
Replacement interval: Lifetime (unless faulty)

Transmission Control Module: Type: ZF 8HP
Operating Voltage: 9 V to 16 V
Part Number: 23456789012
Replacement interval: Lifetime (unless faulty)

Body Control Module: Type: Bosch
Operating Voltage: 9 V to 16 V
Part Number: 34567890123
Replacement interval: Lifetime (unless faulty)

Charging System

Charging Voltage: 13.5 V to 14.5 V

Charging Current: Up to 180 A

Battery Management System: Type: Intelligent Battery Sensor (IBS)
Part Number: 45678901234
Operating Temperature: -40°C to 120°C

Maintenance: Inspect every 30,000 miles

Diagnostic System

Diagnostic Port: Type: OBD-II
Location: Under dashboard, driver's side
Protocols: ISO 9141-2, ISO 14230-4, ISO 15765-4

Diagnostic Tools

BMW ISTA
BMW INPA

Error Codes: Range: P0000 to P2999
Description: Powertrain codes

Maintenance: Check every 30,000 miles

Service Information Service

Detailed service requirements and schedules

30,000 miles

24 months

Inspect battery and charging system
Check all fuses and wiring harness
Inspect lighting system

Perform diagnostic scan for error codes

60,000 miles

48 months

Replace oxygen sensor
Inspect alternator and starter motor
Check control modules for software updates

Perform full electrical system diagnostic

100,000 miles

84 months

Replace battery
Inspect and replace any worn sensors
Check and replace any damaged wiring

Perform comprehensive electrical system check

Frequently Asked Questions

Find answers to common questions about torque specifications

What is the voltage of the battery system in the 2008-2015 BMW 740i?

The 2008-2015 BMW 740i uses a 12-volt electrical system. The battery is a 12V AGM (Absorbent Glass Mat) type, typically rated at 90Ah with a cold cranking amperage (CCA) of 850A.

What is the alternator output for the BMW 740i?

The alternator in the 2008-2015 BMW 740i has an output of 180A at 14V. This ensures sufficient power for the vehicle's electrical systems, including advanced features like the iDrive system and adaptive headlights.

How do I reset the battery registration after replacement?

After replacing the battery, you must register it using a BMW-specific diagnostic tool such as ISTA or a compatible OBD-II scanner with BMW software. This ensures the vehicle's power management system recognizes the new battery and adjusts charging parameters accordingly.

What is the fuse rating for the headlights?

The low-beam headlights in the 2008-2015 BMW 740i are protected by 15A fuses. Always replace fuses with the same rating to avoid electrical damage or fire hazards.

Can I upgrade the electrical system for additional accessories?

Upgrading the electrical system for additional accessories is possible but requires careful planning. Ensure the alternator and battery can handle the increased load. Consult a BMW-certified technician to avoid overloading the system and voiding the warranty.

Factory Service Resources

Access official service manuals, technical documents, and repair guides. These resources provide detailed procedures, specifications, and diagrams directly from the manufacturer.

BMW 740i Electrical System Overview

Coming Soon

Detailed guide covering the electrical system architecture, including wiring diagrams and component locations.

Battery Replacement and Registration Guide

Coming Soon

Step-by-step instructions for replacing the battery and registering it with the vehicle's power management system.

Fuse Box Layout and Specifications

Coming Soon

Comprehensive fuse box layout with fuse ratings and their corresponding circuits for the 2008-2015 BMW 740i.

Alternator Testing and Troubleshooting

Coming Soon

Guide to diagnosing and troubleshooting alternator issues, including voltage output testing and common failure symptoms.

About the Author

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