2021-2022 Audi e-tron Slow Charging P31C500 TSB

Symptoms

Owners of 2021-2022 Audi e-tron models may experience the following issues related to this TSB:

• The battery charging is very slow.
• After charging for 30 minutes or more, the estimated charging time display changes from a normal time to an "excessively long time" (for example, 36 hours or more when connected to a Level 2 charger or DC fast charger).

Fault Codes / DTCs

When these symptoms occur, a diagnostic scan may reveal the following Diagnostic Trouble Code (DTC) stored in the High-voltage battery charger, J1050 (address word 00C6):

Code	Description	Module
P31C500	Temperature sensor coolant inlet excessive	High-voltage battery charger, J1050

Diagnosis / Trigger Conditions

The Audi e-tron slow charging P31C500 issue is primarily caused by an incorrect calibration of the cooling system control valve during vehicle production. This calibration error can lead to an excessive temperature within the cooling system, which directly impacts the battery's charging speed.

Audi has implemented improved tolerances and quality checks at the supplier level to address this production issue in newer vehicles.

Repair Procedure Summary

If your 2021-2022 Audi e-tron exhibits the Audi e-tron slow charging P31C500 symptom, technicians will follow a specific diagnostic and repair process:

1. Check Vehicle History: The technician will first review the vehicle's history for any previously stored DTCs related to coolant valves within the thermal management control module, J1024 (address word 00C5).
2. Output Diagnosis:
   • If a history of coolant valve DTCs exists, an output diagnosis will be performed on the specific valve that previously stored a code. If the values do not change during this test, the corresponding coolant valve will be replaced according to the Elsa Repair Manual, including bleeding the cooling system.
   • If no history of coolant valve DTCs is found, the technician will perform an output diagnosis starting with coolant valve 2 (N633), then coolant valve 4 (N635), and finally coolant valve 3 (N634). If any of these valves show no change in values during the test, the defective valve will be replaced following the Elsa Repair Manual procedures, including cooling system bleeding.
3. Verification: After the repair, the high-voltage battery charging rate will be rechecked to ensure it charges at a normal speed and that the DTC P31C500 is no longer present.

Required Tools or Parts

Technicians will need to consult ETKA for specific part numbers for coolant and fasteners. The following coolant valves may be required, depending on diagnostic findings:

• 4KE963375J: Coolant valve 2 (N633)
• 4KE963375N: Coolant valve 4 (N635)
• 4KE963375H: Coolant valve 3 (N634)

Important Warnings

• Only replace the actual valve that is defective. This prevents unnecessary part replacements and ensures the correct component is addressed.

Warranty Information

This repair is covered under warranty for:

• Vehicles up to 48 months or 50,000 miles.
• Certified Pre-Owned (CPO) vehicles under the G10 claim type, after owner verification.

If the vehicle is outside of any applicable warranty, this Technical Service Bulletin serves as informational guidance for diagnosis and repair.

This TSB, reference number 2064025/3, dated October 19, 2021, supersedes Technical Service Bulletin Group 19 number 21-23, dated September 22, 2021.

Source: NHTSA ID 10202582