Hitachi ALR0558 Charging System Voltage Regulator

Hitachi ALR0558 Voltage Regulator Overview

Hitachi ALR0558 is a charging system voltage regulator for select Audi and Volkswagen applications with Bosch alternators. It controls alternator output so the battery recharges at the proper voltage while helping protect sensitive electrical components.

Built with quality internal components, this regulator supports stable charging performance in vehicles such as the Audi A6 Quattro, Audi A8 Quattro, and Volkswagen Passat. If you are replacing a failing charging system voltage regulator, Hitachi ALR0558 provides a direct-fit service part for the listed applications.

Key Features

• Charging system voltage regulator for alternator output control
• Helps maintain safe battery charging voltage
• Supports protection of vehicle electrical components
• Uses quality components for durability and reliable operation
• Fits select Audi and Volkswagen models with Bosch alternators
• Part number: ALR0558

Detailed Product Description

Hitachi ALR0558 is designed for vehicles that require precise alternator voltage regulation to keep the charging system operating within specification. It is used in applications including 1995-1999 Audi A6 Quattro with Bosch alternator, 2000-2004 Audi A6 Quattro, 1997-2003 Audi A8 Quattro, 2001-2003 Audi S8, and 2000-2001 Volkswagen Passat. The part number ALR0558 is also listed for additional Audi and Volkswagen fitments, including 2002-2005 Volkswagen Jetta and select Audi S6 and A4 applications.

This part cross-references ALR0558-D for the same application.

What It Helps Address

• Overcharging that can damage the battery or electrical system
• Undercharging that can leave the battery weak or discharged
• Fluctuating alternator output and unstable charging voltage
• Charging-system warning lights related to regulator failure
• Electrical component stress caused by inconsistent voltage control

Installation Notes and Tips

Verify alternator type and vehicle fitment before ordering, especially on Bosch alternator applications. Confirm the model year, engine configuration, and charging system details against the listed fitment for ALR0558. Professional installation is recommended, and the alternator should be inspected for wear or damage during replacement.

Quality Assurance

Hitachi voltage regulators use quality components to support reliability and durability in charging-system service. This makes ALR0558 a practical replacement choice for Audi and Volkswagen vehicles that require controlled alternator output.