2021-2024 Audi Q5 e / A7 e Red Electrical System Fault P0AC000

Owners of 2021-2024 Audi Q5 e and A7 e vehicles may encounter a critical warning message in their instrument cluster, stating "Electrical system: fault. Safely stop vehicle." This condition can also lead to the vehicle being unable to start. Audi Technical Service Bulletin (TSB) 2076748/1 provides guidance for diagnosing and addressing this specific issue, particularly when the Diagnostic Trouble Code (DTC) P0AC000 is present. This TSB helps resolve the Audi Q5 e red electrical system fault P0AC000.

This TSB 2076748/1 supersedes the previous Pending Service Solution (PSS) TSB 2074901, offering updated procedures for technicians.

Symptoms

Drivers may observe the following symptoms related to this electrical system fault:

• A prominent red warning message displayed in the instrument cluster: "Electrical system: fault. Safely stop vehicle."
• The vehicle may be unable to start, preventing operation.

Fault Codes / DTCs

When diagnosing this issue, workshops typically find the following event memory entry logged in the control unit for hybrid battery management (diagnostic address 008C):

• P0AC000: "Hybrid/EV Battery Pack Current Sensor "A" Circuit Range/Performance" (symptom ID: 14340)

It is important to note that if any of the following DTCs are also logged in the hybrid battery management control unit (diagnostic address 008C), this specific TSB may not apply, indicating a different root cause:

• P0AA700: Hybrid/EV Battery Voltage Isolation Sensor Circuit
• P0AA100: Hybrid Battery Positive Contact Circuit Stuck Closed
• P0AA200: Hybrid/EV Battery Positive Contactor Circuit Stuck Open
• P0AA400: Hybrid/EV Battery Negative Contact Circuit Stuck Closed
• P0AA500: Hybrid/EV Battery Negative Contact Circuit Stuck Open

Diagnosis

To properly diagnose the Audi Q5 e red electrical system fault P0AC000, technicians will perform several checks:

1. Confirm the customer's reported symptoms, such as the warning message and no-start condition.
2. Verify the presence of DTC P0AC000 in the hybrid battery management control unit (diagnostic address 008C).
3. Ensure that the other related DTCs (P0AA700, P0AA100, P0AA200, P0AA400, P0AA500) are not present, as their presence would indicate a different underlying issue.
4. Check the software version of the high-voltage battery switching unit (-SX6-). The applicable software versions for this TSB are 0108 or 0208. This check is performed using Guided Functions in ODIS, navigating to diagnostic address 008C, then selecting "Guided Function," "Read identification," and finally "Read additional identification data" to display identification data of sub-systems (slaves). The result is shown in the diagnostic log.

Important Warnings for Technicians and Owners

Audi TSB 2076748/1 includes critical advisories that must be followed:

• This TSB does not apply if repair measures have already been described in a different TSB or if the repair is required due to an accident.
• Replacing parts or attempting repairs will not fix the problem. Unjustified work or replacement parts will be charged back, and invoicing under warranty is not permitted for such actions.

Repair Procedure Summary

For the Audi Q5 e red electrical system fault P0AC000, Audi TSB 2076748/1 outlines a specific procedure focused on activating the vehicle's bus sleep mode to clear the fault. This involves several steps:

1. Activate bus sleep mode:
   • Lock the vehicle.
   • Ensure no electrical equipment is active, meaning contactors must be open.
   • Confirm the vehicle is no longer connected to a charger.
2. Erase event memory entries: After the bus sleep cycle is complete, all event memory entries must be erased.
3. Re-assess the issue: The technician will then re-assess whether the issue still occurs.

If the complaint persists after this bus sleep cycle, technicians are instructed to submit a TAC (Technical Assistance Center) ticket or TAC Web ticket. The number of this TSB (2076748/1) must be included in the field for additional information on workshop findings to allow the internal department to identify the connection quickly.

Warranty Information

Warranty claims related to this TSB must adhere to the Audi Warranty Policies and Procedures Manual. Claims are subject to review or audit by Audi Warranty.

• Claim Type: If the vehicle is outside of any warranty, this Technical Service Bulletin is informational only.
• Service Number: 9327
• Damage Code: 0039

The following labor operations are associated with this procedure:

• Check vehicle (bus sleep mode): Labor Operation 0689 0199, 10 Time Units (TU).
• GFF / Guided Functions: Labor Operation 0150 0060, time stated on the diagnostic protocol.
• GFF: Labor Operation 0150 0010, refer to SRT (Standard Repair Time) with associated operations.

All part and service references in TSB 2076748 are subject to change. Technicians should always consult the Parts Department and/or ETKA for the latest information and parts bulletins, and the Repair Manual for fasteners, bolts, nuts, and screws requiring replacement.

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Source: NHTSA ID: 10248888