2021-2023 Audi e-tron Electric Drive Motor Leak TSB

Audi has released Technical Service Bulletin (TSB) 2073858/4 to address concerns regarding electric drive motor coolant leaks in certain e-tron models. This bulletin, dated November 7, 2024, supersedes a previous bulletin (Group 93 number 24-25 dated October 24, 2024) and provides updated diagnostic and repair information for technicians. Owners of affected vehicles may experience a "Drive System/Electrical System Malfunction" message in the instrument cluster.

Symptoms

Owners may observe a "Drive System/Electrical System Malfunction" message displayed in the instrument cluster. The specific warning message that appears is:

• "Electrical system: malfunction! Safely stop vehicle"

This warning may not always be present at the time of inspection, but it indicates a potential issue with the electric drive system. The underlying cause is often an internal coolant leak within the electric drive motor.

Fault Codes / DTCs

A key indicator of this issue is the storage of Diagnostic Trouble Code (DTC) P0AA600. This code is typically stored in the Battery manager control module -J840- (address word 008C) and signifies a Hybrid/EV Battery Voltage System Isolation fault.

Important Warnings for Owners

Audi has issued several critical advisories within TSB 2073858/4 that owners should be aware of:

• "Vehicles should never be operated without a correctly filled cooling system."
• "The power electronics for electric drive must not necessarily be replaced if the electric drive motor is leaking (refer to images 4 and 5)."
• "In this case, the power and control electronics for electric drive must not be replaced." (This applies specifically if corrosion on the high-voltage system connection or condensation on the high-voltage system connection cover is the cause, not an actual leak).
• "If the power and control electronics for electric drive must be replaced as a group, then this must be billed separately (see warranty accounting instructions)."
• "If the vehicle is outside of any warranty, this Technical Service Bulletin is informational only."

Diagnosis and Trigger Conditions

Technicians will investigate the presence of DTC P0AA600 and perform a detailed inspection for internal coolant leaks within the electric drive motor. This involves checking the coolant drip container and active chambers on both the front and rear axles.

Specific findings that indicate a leak include:

• An overflowing coolant drip container.
• Coolant leaking from the active chamber, particularly in low-mileage vehicles.

It is important to note that a few milliliters of coolant leakage from the resolver cover is considered normal and not a technical issue. However, no coolant should escape from the bores of the active chamber. The TSB also clarifies that the power electronics for the electric drive should not be replaced if the motor is leaking, unless specific conditions warrant it. Furthermore, if corrosion on the high-voltage system connection or condensation on its cover is found (as depicted in Figures 4 and 5 of the TSB), the power and control electronics for the electric drive must not be replaced.

Repair Procedure Summary

The repair process outlined in TSB 2073858/4 focuses on accurately identifying and repairing the source of the coolant leak.

1. Leak Check: Technicians will first check for coolant leaks on both the front and rear electric drive motors.
2. Seal Inspection: The seal on the coolant expansion tank must be checked and re-secured if necessary.
3. Component Replacement (if necessary): Depending on the leak's location and severity, the procedure may involve replacing the front electric drive motor, rear electric drive motor, or both for e-tron S models.
4. Power and Control Electronics: The bulletin provides specific guidance on when to replace the power and control electronics for the electric drive. This replacement is only performed if necessary and is billed separately if done as a group.
5. High-Voltage System Management: The high-voltage system will be deactivated and activated as part of the repair.
6. Battery Charge and Diagnostics: The battery will be charged, and a Guided Fault Finding (GFF) procedure will be performed.
7. Test Drive: A test drive is required both before and after the service procedure to verify the repair.

Required Tools or Parts

Technicians will consult ETKA/ELSA for the latest information on required parts and tools. This includes fasteners, bolts, nuts, and screws as needed per the repair manual. Specific parts that may be required include:

• Front drive motor
• Rear drive motor
• Rear drive motors (for e-tron S models)
• Front drive motor power electronics
• Rear drive motor power electronics

Warranty Information

For vehicles within warranty, repairs performed under TSB 2073858/4 will be covered. The bulletin specifies various service numbers and damage codes for warranty claims:

• Service Number 9340: For replacement of the front electric drive motor.
• Service Number 9346: For replacement of the rear electric drive motor.
• Service Number 9350: For replacement of the power and control electronics for the electric drive.
• Damage Codes: 0050 (for motor replacements) and T055 (for power and control electronics replacement).

If the vehicle is outside of its warranty period, this Technical Service Bulletin serves as informational guidance, and repair costs may apply to the owner.

Owner Action

If you own a 2021-2023 Audi e-tron and experience a "Drive System/Electrical System Malfunction" message, or suspect a coolant leak from your electric drive motor, it is crucial to contact your authorized Audi dealership. Inform them about the symptoms and mention Technical Service Bulletin 2073858/4. The dealership's trained technicians can perform the necessary diagnostics, including checking for DTC P0AA600, and carry out the appropriate repair procedures as outlined by Audi.

NHTSA ID: 11011291