2021-2023 Audi e-tron Electric Motor Leak P0AA600 TSB

Owners of 2021-2023 Audi e-tron and e-tron Sportback vehicles may encounter various warning messages in the instrument cluster, accompanied by an electric motor leaking condition and the diagnostic trouble code (DTC) P0AA600. This issue is addressed by Audi Technical Service Bulletin (TSB) 2073858/10, which was released for publishing on September 25, 2025, for the United States market.

Symptoms

Owners typically report a 'Drive System/Electrical System Malfunction' message appearing in the instrument cluster, often alongside an 'Electrical system: malfunction! Safely stop vehicle' warning lamp. Other symptoms indicating a potential issue with the electric drive motor or transmission include:

• Noises and vibrations, such as pinging, vibrating, jerking, or general noise.
• Functionality issues, including the system not switching on/activated, misfire, no function, or not switching on/connecting.
• Leaks described as 'not watertight' in the transmission assembly.

Fault Codes / DTCs

When diagnosing these symptoms, technicians may find the following diagnostic trouble code (DTC) stored in the Battery manager control module -J840- (address word 008C):

Code	Description
P0AA600	Hybrid/EV Battery Voltage System Isolation

Diagnosis / Trigger Conditions

The core issue identified is damage to the electric drive motor due to an internal coolant leak. During a workshop visit, an internal leak might be determined if the coolant drip container is found to be full, or if coolant is observed leaking from the active chamber on either the front or rear axle.

It is crucial to check the seal on the coolant expansion tank beforehand and re-secure it if any work is performed. Vehicles should never be operated without a correctly filled cooling system.

Repair Procedure Summary

The repair process focuses on identifying and localizing the source of the coolant leak. This involves inspecting the electric drive motor on both the rear and front axles.

For the rear axle, technicians will check the drip container:

• If the drip container is overflowing, coolant is leaking from the active chamber.
• If the drip container is empty, coolant is still leaking from the active chamber, particularly in vehicles with low mileage.

For the front axle, coolant leaking from the active chamber is also a key indicator. A few milliliters of coolant leakage from the resolver cover is not considered a technical issue. However, no coolant should escape from the active chamber bores.

Important Cautions:

• The power electronics should not be replaced if the electric drive motor is simply leaking.
• If the drive motor is replaced without changing the gearbox, technicians must refer to the Workshop Manual for instructions on calibrating axial clearance and using the correct shims. Incorrect shim usage can lead to gearbox noises after repairs.
• If the power and control electronics for the electric drive must be replaced as a group, they must be billed separately according to warranty accounting instructions.

Owner Action

If your 2021-2023 Audi e-tron or e-tron Sportback is displaying warning messages like 'Drive System/Electrical System Malfunction' or you suspect an electric motor coolant leak, and especially if you encounter the Audi e-tron P0AA600 fault code, it is recommended to schedule an appointment with an authorized Audi service center. They can perform the necessary diagnostic checks and repairs as outlined in TSB 2073858/10. Warranty claims are subject to Audi's policies and procedures; if your vehicle is outside of warranty, this TSB is for informational purposes only.

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Source: NHTSA ID 11023762