48-Volt Mild Hybrid Systems: Audi

Details Posted on 11 January 2024 | Share:

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Mild hybrid systems are not new. They were some of the first hybrid vehicles to be put into production. The 48-volt mild hybrid system is now becoming more common among some vehicle makers. What consideration are there for repairing a vehicle equipped with a 48-volt mild hybrid system? Let’s see what Audi has to say.

Audi introduced the 48-volt mild hybrid system on several models in 2019. The 48-volt system is used to support the advance start/stop mode using a belt-driven start-alternator and roll stabilization.

The 48-volt system information can be found in the vehicle-specific Electrical Equipment Repair Manual ➤ 27 - Battery, Starter, Generator, Cruise Control. Review the vehicle build data to confirm which batteries are equipped.

Per Audi service information:

• "The 12V system is supported by the 48V system via the Voltage Converter, 48V/12V -A7-. So the only way for the 12V vehicle electrical system to be de-energized is to de-energize the 48V system beforehand.
• "To de-energize the 48V system, perform the de-energizing test plan” this is done with a scan tool."

Per Audi emergency response guides (ERG):

• "...in order to deactivate the on-board power supply the 48V Lithium-ion battery has to be separately disconnected in addition to the 12V lead acid battery."
• The negative wire of the 48-volt system is colored brown and purple.

Per the Audi Guideline For Rescue Forces:

"48 volt lines can be identified by their colour, which is purple. Vehicles with 48-volt technology may have subsystems installed that operate in the high-voltage range (alternating current greater than 30 volts). If this is the case, the cables to these system components can be identified by orange warning colour."

The OEM Hybrid and Electric Vehicle Disable Search features battery layouts and step-by-step directions to locate the procedure to disable the 48-volt system.

For additional Audi information, check out the Audi OEM Information page.

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