2021-2024 Audi e-tron ABS Control Module No Communication TSB

Audi has released Technical Service Bulletin (TSB) 2073483/1 to address a specific issue affecting the ABS/ESC control unit in certain e-tron models. This bulletin focuses on situations where the ABS/ESC control unit cannot be reached, leading to the diagnostic trouble code (DTC) U012100, which indicates "ABS Control Module no communication." Owners experiencing this problem might notice reduced braking assistance and various warning lights on their instrument cluster. This TSB provides important guidance for technicians and owners regarding the diagnosis and temporary management of this condition.

This issue primarily impacts 2021-2024 Audi e-tron, e-tron Sportback, Q8 e-tron, and SQ8 e-tron vehicles equipped with Software Level 321 in the ABS control unit -J104-. The underlying cause is a rare restart of the control unit -J104-, which can cause the electromechanical brake servo to remain in a hydraulic fallback state, disrupting bus communication within the vehicle. Understanding this specific condition is key to properly addressing the Audi e-tron ABS communication problem.

Symptoms You Might Notice

Owners of affected Audi e-tron vehicles may observe several signs indicating an issue with the ABS control module communication:

• Reduced braking assistance: The vehicle's braking performance may feel diminished.
• Warning lamps: Various warning lights may illuminate in the instrument cluster, signaling a system malfunction.
• Communication loss: The ABS/ESC Control unit -J104- (Diagnostic address 0003) may be unreachable for communication during diagnostics.

Fault Codes / DTCs

When diagnosing this issue, specific diagnostic trouble codes (DTCs) will be stored in the vehicle's system:

• U012100 (Symptom Code 19875): "ABS Control Module no communication" is logged, typically in diagnostic address 0001.
• P060A00: "Control module internal processor monitoring malfunction" may also be logged as a passive or intermittent fault in other control units.

Diagnosis and Trigger Conditions

This Technical Service Bulletin (TSB 2073483/1) specifically applies to Audi e-tron and Q8 e-tron variant vehicles that have Software Level 321 installed in the ABS control unit -J104-. If your vehicle has a different software level, Audi advises referring to TSB 2072977 for appropriate guidance.

The technical background explains that the control unit -J104- can perform an unexpected restart. Following this restart, the electromechanical brake servo enters a hydraulic fallback level, and bus communication ceases. This sequence of events can trigger various driver messages from other vehicle systems. Audi notes that this control unit restart is a very rare occurrence.

Important Warnings for Owners

Audi has provided specific instructions and warnings regarding this condition:

• "If the customer's vehicle condition matches the condition listed in the Technical Background of this PSS, explain to the customer that a solution is expected to be available by the end of the 3rd quarter of 2024 (subject to change) and that no repairs are necessary at this point."
• "Do not replace any components for this condition since this will not resolve the customer's concern."

These warnings are crucial as they indicate that component replacement is not the current solution, and a software-based fix is anticipated later in 2024.

Repair Procedure Summary

The repair procedure outlined in TSB 2073483/1 involves a diagnostic approach rather than immediate component replacement, especially for vehicles with the specific software level and symptoms related to the Audi e-tron ABS communication issue. For vehicles equipped with ABS/ESC control unit -J104- with software version SW 321, the following steps are recommended:

1. Initial Diagnosis: Technicians should first diagnose the vehicle to confirm the condition aligns with the technical background described in the TSB.
2. Customer Communication: If the condition matches, customers should be informed that a permanent solution is expected by the third quarter of 2024, and no repairs are necessary at the current time.
3. Avoid Component Replacement: It is explicitly stated that components should not be replaced for this condition, as it will not resolve the underlying issue.
4. Temporary Resolution Steps: To temporarily restore communication and clear fault codes:
   • Disconnect the 12V battery from the vehicle for five minutes.
   • After reconnecting, check the accessibility of the control unit -J104- in the diagnosis system.
   • Delete any intermittent DTCs, including "P060A00, Control module internal processor monitoring malfunction," from other control units.
   • Recheck control unit -J104- after switching the ignition off and back on.
   • If communication is correct and no other DTCs are present in diagnostic address 0003, the vehicle can be released.
5. Further Diagnostics: If additional DTCs are still stored in diagnostic address 0003, technicians should follow the General Guided Fault Finding (GFF) instructions.

Owner Action

If you own a 2021-2024 Audi e-tron, e-tron Sportback, Q8 e-tron, or SQ8 e-tron and are experiencing symptoms such as reduced braking assistance or warning lights related to the ABS system, particularly with the "ABS Control Module no communication" message or DTC U012100, it is important to contact an authorized Audi service center. Reference TSB 2073483/1 when discussing the issue with your dealer.

Audi anticipates a permanent solution to be available by the end of the third quarter of 2024. For warranty claims, this service bulletin is covered under the 110 warranty for up to 48 months or 50,000 miles. Certified Pre-Owned (CPO) vehicles may also be covered under G10. If your vehicle is outside of these warranty periods, this information serves as a reference.