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What Is the Extra Round Plug on the Mercedes-Benz 38-Pin Adapter?

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Home › Questions & Answers › What Is the Extra Round Plug on the Mercedes-Benz 38-Pin Adapter?
Applies to: UCAN-II, UCAN-II Pro

The round plug on the Mercedes-Benz 38-pin adapter is an optional 12V power connection for the ECU.

  • You do not need to connect it if the vehicle has a good battery
  • It can be used to power the ECU with an external 12V power supply if the vehicle’s battery is dead or disconnected

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🛒 SHOP
  • PRODUCTS
    • UCAN-II PRO
    • UCAN-HD-A
    • Oscilloscope
    • High Capacity Jump Starter RB6000A
    • Battery & Charging System Tester
    • Adapters
    • All Products
    • Rent a Scanner
  • LEARN
    • Find by Vehicle
    • Video Library
    • Scanner Resources
    • Mechanic Fixes
    • Success Stories
    • Community Forum
    • Glossary
    • Advanced Vehicle Data by VIN
    • Share a Fix ✦
  • TOOLS
    • VIN Decoder Basic – Free
    • VIN Decoder – Advanced
    • Recall Check
    • DTC Code Library
    • Parts Lookup
    • DIY Repair Savings Calculator
    • Owner’s Manual
    • Maintenance Schedule Lookup
    • Battery Group Finder
    • Used Car Inspection Checklist
    • Vehicle Market Value
  • SUPPORT
    • FAQs
    • Product Support
    • Coverage Check
    • Track Order
    • Product Resources
    • Talk to a Mechanic
  • ABOUT
    • About Us
    • Contact Us
    • Press
    • Right to Repair: Every Car Owner’s Right

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