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

Owners of 2021-2023 Audi e-tron and e-tron Sportback vehicles may experience a specific issue related to the electric drive motor. This technical service bulletin, 2073858/1, addresses instances where an internal coolant leak in the electric drive motor triggers a warning message and a diagnostic trouble code.

Symptoms

If your vehicle is affected, you might observe a "Drive System/Electrical System Malfunction" message appearing in the instrument cluster. This warning indicates a potential problem with the drive or electrical system. The message may not always be present when the vehicle is inspected.

Fault Codes / DTCs

Technicians may find the following diagnostic trouble code (DTC) stored in the Battery manager control module -J840- (address word 008C):

Code	Description	Module
P0AA600	Hybrid/EV Battery Voltage System Isolation	Battery manager control module -J840-

This DTC P0AA600 specifically points to an isolation fault within the hybrid/EV battery voltage system.

Diagnosis / Trigger Conditions

During a workshop visit, an internal coolant leak in the electric drive motor is typically identified. This can manifest as a full coolant drip container or coolant leaking from the active chamber on either the front or rear axle. The technical background for this issue is damage to the electric drive motor caused by this internal coolant leak.

For the rear axle, an overflowing drip container or coolant leaking from the active chamber indicates a problem. If the drip container is empty, coolant may still be leaking from the active chamber, particularly in lower mileage vehicles.

For the front axle, coolant leaking from the active chamber is the primary indicator. It's 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.

Important Warnings

• Vehicles should never be operated without a correctly filled cooling system. Operating a vehicle with insufficient coolant can lead to further damage.
• The power electronics for the electric drive must not be replaced if the electric drive motor is leaking. This means the focus should be on addressing the motor leak itself, not immediately replacing the power electronics.
• If the power and control electronics for the electric drive must be replaced as a group, this will be billed separately according to warranty accounting instructions.

Repair Procedure Summary

The repair process for the Audi e-tron P0AA600 issue involves several key steps to address the coolant leak and its effects:

1. Coolant Leak Localization: The first step is to thoroughly check for and localize the source of the coolant leak within the electric drive motor system.
2. Coolant Expansion Tank Seal: If it's determined that the electric drive motor is damaged due to an internal coolant leak, the seal on the coolant expansion tank must be checked and re-secured after any necessary work is performed.
3. Motor Replacement (if necessary): If the electric drive motor is confirmed to be damaged by the internal coolant leak, it will need to be replaced. This applies to both front and rear electric drive motors.
4. Power and Control Electronics: In specific cases, the front or rear power and control electronics for the electric drive may also require replacement, especially for e-tron S models where two rear electric drive motors are present.

Required Tools or Parts

Specific fasteners, bolts, nuts, and screws, as well as the front and rear drive motors and their associated power electronics, may be required. Technicians should consult ETKA (Electronic Parts Catalog) and ELSA (Electronic Service Information System) for the latest information and part numbers relevant to the repair.

Warranty Information

For vehicles outside of warranty, this Technical Service Bulletin 2073858/1 serves as informational guidance only. Warranty claims are submitted in accordance with the Audi Warranty Policies and Procedures Manual.

Specific service numbers and damage codes are used for warranty claims:

• Service Number 9340: For replacement of the front electric drive motor (Damage Code 0050).
• Service Number 9346: For replacement of the rear electric drive motor (Damage Code 0050).
• Service Number 9350: For replacement of the power and control electronics for electric drive (Damage Code T055). This must be billed separately.

Labor operations are also detailed with specific time units (TU) for tasks such as checking for leaks, replacing motors, and replacing power electronics. Diagnostic time (GFF) and test drive allowances are also specified.

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Source: NHTSA ID: 11005962