2021-2024 Audi 12V Battery Drained Diagnosis TSB

Symptoms of a Drained 12V Battery

The primary symptom addressed by this Technical Service Bulletin (TSB) is a vehicle's 12V battery being drained. This can manifest as an inability to start the vehicle or other electrical system malfunctions. When an Audi 12V battery drained condition is reported, technicians must investigate the root cause before proceeding with replacement.

Important Warnings for Owners

Audi has issued specific guidelines regarding the 12V battery to ensure proper diagnosis and to clarify warranty coverage. Owners should be aware of the following:

• "Replacement of drained or damaged batteries due to external influence is not applicable to warranty and claims regarding such cases may be denied."
• "Please ensure that the battery is not drained due to an external influence: Keeping the ignition on for a prolonged amount of time."
• "Parking the vehicle for a prolonged amount of time without a battery maintainer being attached (>90 days)."
• "Non-OEM accessories being attached to the vehicle that may use electrical power while the vehicle is parked."
• "Please ensure that the vehicle batteries are at an acceptable state of charge when the vehicle arrives at the service center."
• "If the vehicle is parked for a prolonged amount of time (for example, waiting for parts), periodic (at least monthly) checks should be performed regarding the battery's state of charge."
• "If the battery's state of charge is below 80%, the battery should be recharged immediately."
• "Note: In some cases, the battery may be too low to allow the battery charger to start up. In such cases, the charger can be started by 'jump starting' it by connecting jumper cables from a good battery to the damaged battery for a moment while the charger is connected. (The jumper cables only have to be touched to the poles as the vehicle charger needs to see an initial voltage to start up. They can be taken off as soon as the vehicle charger starts charging.)"
• "According to the owner's manual, the customer is responsible to service (charge) the 12V battery after one month of the vehicle not being driven."
• "Should an entry here show a duration of last standing time of more than ~750h, combined with a large battery discharge and under-voltage time under section 1, the battery may be defective due to an external influence."

Diagnosis Procedure for a Drained 12V Battery

When a technician encounters an Audi 12V battery drained condition, a specific diagnostic procedure using the Offboard Diagnostic Information System (ODIS) is required. This process helps determine if external factors or vehicle misuse led to the battery discharge.

1. Connect a Battery Charger: The technician must first connect a 12V battery charger to the vehicle.
2. Access ODIS Guided Functions: Within ODIS, navigate to "GFF >> 19 - Diagnostics interface for databus >> Guided Functions >> Reading history data."
3. Select Data Display Option: Choose option "-1- Display of the broken down data with the option to limit the period" to view detailed battery history.
4. Input Structured Data Selection: On the "Structured data" screen, enter the sequence "1,2,3,4,5,6,7,8" to access various history data points, including static voltage shortfalls, current exceeded, shut-off stage history, and energy balance.
5. Specify Time Period: Input the desired number of days for which the history data should be evaluated. This allows for focused analysis of recent battery activity.
6. Review Battery History: ODIS will then output the battery history data to the screen and store it in the GFF log. This data includes information from "Section 5 - Energy critical conditions," which details parameters when the vehicle couldn't start due to a low 12V battery (e.g., ignition left on, lights on). It also includes data from "Section 7 - Energy balance standing," showing the time and discharge during parking periods.

This comprehensive data helps the technician identify if the drained battery was caused by external influences or misuse, such as prolonged ignition-on time or extended parking without a battery maintainer.

Warranty Information

For warranty claims related to a drained 12V battery, the TSB specifies that the time spent performing the GFF diagnostic procedure should be claimed on the same warranty claim as the battery replacement. However, as noted in the warnings, batteries found to be drained or damaged due to external influences are typically not covered under warranty.

NHTSA ID: 10242920