48-Volt Mild Hybrid Systems: Audi

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.

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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