2021 Audi e-tron Insufficient Cabin Heating TSB

Symptoms

Owners of 2021 Audi e-tron vehicles may experience Audi e-tron insufficient heating from the HVAC system. Common symptoms include:

• Insufficient or uneven cabin heating performance.
• The cabin heating may be slow to get warm.
• The engine coolant may appear discolored, often described as "brownish” discoloration or containing suspended particulate matter.

Diagnosis

The root cause of this issue is typically contaminants in the engine coolant that obstruct the flow through the heater core, diminishing the HVAC system's ability to heat the cabin. Technicians can diagnose this by observing a drastic temperature difference between the inlet and outlet heater hoses to the heater core, with the inlet being significantly warmer than the outlet. This temperature difference indicates an obstruction within the heater core.

Visual inspection of the coolant and the coolant reservoir may reveal the presence of suspended particulate matter or a general discoloration. It's important to note that this contamination is not engine oil or transmission fluid.

Important Warnings

Audi has issued critical warnings regarding the repair process:

• "Risk of scalding due to hot coolant. The cooling system is under pressure when the engine is warm. Risk of scalding due to hot steam and hot coolant."
• "Do not reuse any of the cleaning and coolant solutions used during this process."

Repair Procedure Summary

Addressing the Audi e-tron insufficient heating issue involves a comprehensive cleaning and flushing procedure of the cooling system. The general steps are as follows:

1. Prepare the System: The cooling system is cleaned and flushed using a specialized cooling system cleaning set (part number G 052 525 A3).
2. Drain Coolant: The existing coolant is drained from the system while the engine is warm and the coolant thermostat is open, following procedures outlined in ElsaPro.
3. Flush Heater Core: The heat exchanger(s) are flushed with water in the opposite flow direction, ensuring water pressure does not exceed 2 bar. After flushing, the coolant is blown out of the heat exchanger(s) in the opposite flow direction.
4. Initial Cleaning Cycle: The cooling system is filled with 3.0 liters of cooling system cleaner 'S' and the remaining balance with coolant. The engine is run for 90 minutes with cabin heating set to full hot and high fan speed. Rear HVAC units, if equipped, should also be set to full hot and high fan.
5. Drain Cleaning Solution: The cleaning solution is then drained from the system.
6. Neutralizer Cycle: The system is refilled with 3.0 liters of neutralizer 'S' and coolant. The engine is run for 15 minutes with cabin heating set to full hot and high fan speed.
7. Drain Neutralizer Solution: The neutralizer solution is drained.
8. Distilled Water Rinse: The cooling system is filled with plain distilled water, and a bleeding procedure is performed. The engine is run at approximately 2000 RPM until the cooling fans activate, continuing for an additional 3 minutes. This distilled water fill is then drained. This rinse process is repeated for an additional cycle.
9. Final Fill: The cooling system is filled with the proper mix ratio of new coolant and distilled water, following ElsaPro procedures, and a final bleeding procedure is performed.
10. Heater Core Replacement (If Necessary): If normal cabin heating performance is not restored after this extensive cleaning and flushing procedure, and the root cause is confirmed to be an obstructed heater core, then the heater core must be replaced.
11. Coolant Expansion Tank Replacement (If Necessary): If the coolant expansion tank remains discolored after the cleaning process, it must also be replaced.

Required Tools and Parts

Technicians will require specific tools and parts to perform this repair:

• Cooling system cleaning set: Part number G 052 525 A3
• Cooling system cleaner 'S': Included in the cleaning set.
• Neutralizer 'S': Included in the cleaning set.
• Coolant: Approximately 30 liters.
• Analog Refractometer: Tool number T10007B.
• Cooling system charge kit: Tool number VAS 6096.
• Adapter: Tool number VAG 1274/X.
• Fasteners, Bolts, Nuts, and Screws: As needed per the repair manual (See ETKA).

Warranty Information

This repair may be covered under warranty, depending on the vehicle's age and mileage:

• Standard Warranty: Up to 48 months or 50,000 miles.
• CPO Covered Vehicles: G10 for Certified Pre-Owned vehicles, subject to owner verification.
• If the vehicle is outside of any applicable warranty, this Technical Service Bulletin serves as informational guidance only.

The Service Number for this procedure is 8023, and the Damage Code is 0016. Labor operations include "Drain and fill cooling system (4 x drain, fill and bleed operations)" with code 1938 17XX.

Owner Action

If you are experiencing Audi e-tron insufficient heating or notice discolored coolant in your 2021 Audi e-tron, it is recommended to schedule an appointment with an authorized Audi service center. Describe the symptoms clearly to the service advisor. The technicians will follow the detailed procedures outlined in TSB 2062583/1 to diagnose and resolve the issue.

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Source: NHTSA ID 10189324