2023-2024 Audi A3/S3/RS3 Engine Warning Lamp DTC U031700

Symptoms

Owners of 2023-2024 Audi A3, S3, and RS 3 models may notice the engine warning lamp (MIL) illuminated on their dashboard, specifically observing the message "The MIL is on." This indicates a potential issue with the vehicle's systems, often accompanied by a discharged 12-volt battery.

Fault Codes / DTCs

When the engine warning lamp is on, a diagnostic scan may reveal the following fault code stored in the Battery Management 2 (Battery 48V) control module, which corresponds to address word 0021:

Code	Description	Symptom Code	Status
U031700	Control Module Timer/Clock Performance	32782	Passive/sporadic OR Active/static

This Audi A3 engine warning lamp U031700 code points to an issue related to the control module's timer or clock performance, often triggered by a low battery state.

Diagnosis / Trigger Conditions

The primary cause for the engine warning lamp and DTC U031700 is a discharged 12-volt vehicle battery. This condition typically arises if the vehicle has been stationary for an extended period without being driven. The Battery Management 2 system detects this low voltage, leading to the logged fault. Technicians are advised that this problem commonly occurs when the vehicle is not driven for an extended period.

Repair Procedure Summary

For the Audi A3 engine warning lamp U031700 issue, the repair involves a straightforward process to restore the 12-volt battery's charge. Technicians are instructed to manually charge the 12-volt vehicle battery. This manual charging procedure is designed to rectify the discharged battery condition. Once the battery is fully charged, the fault should clear, and the engine warning lamp should turn off. The vehicle can then be returned to the customer as soon as the fault has been rectified.

Important Warnings for Owners

Audi advises that this problem may reoccur if the vehicle is not driven for an extended period. To prevent future occurrences of the engine warning lamp and DTC U031700 due to a discharged battery, Audi recommends consulting your Owner's Manual regarding the use of a battery maintenance unit when the vehicle will be stationary for an extended duration. This will help keep the 12-volt battery adequately charged and prevent the "The MIL is on." message from reappearing.

Warranty Information

This Technical Service Bulletin 2074713/1 outlines specific warranty claim details for dealers. If the vehicle is outside of its warranty period, this TSB serves as informational guidance only. The relevant warranty codes are:

• Service Number: 2707
• Damage Code: 0040
• Diagnostic Time: GFF - Checking and clearing fault codes included in existing labor operations (0151 0060), and GFF (0151 0010) for time stated on the diagnostic protocol and associated operations.
• Claim Comment: As per TSB 2074713/1

All warranty claims must adhere to the Audi Warranty Policies and Procedures Manual and are subject to review by Audi Warranty.

Owner Action

If your 2023-2024 Audi A3, S3, or RS 3 displays an engine warning lamp, it is recommended to have your vehicle diagnosed by an authorized Audi service center. They can confirm the presence of DTC U031700 and perform the necessary manual 12-volt battery charging procedure as outlined in Technical Service Bulletin 2074713/1. This repair is typically covered under warranty if the vehicle is still within its warranty period, though claims are subject to Audi's warranty policies.

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Source: NHTSA ID: 11005864