2024-2025 BMW Vehicles Distorted Bluetooth Call Audio

BMW has released Service Information Bulletin (SIB) 84 02 25 to address a common complaint regarding distorted voice quality during Bluetooth phone calls in various 2024-2025 BMW vehicles. Owners of affected models, including the BMW X5, may find that the person they are speaking with reports a distorted voice reproduction when using the vehicle's integrated Bluetooth system, particularly with iPhone 14 and earlier devices.

This issue specifically impacts calls made via BMW Bluetooth and does not affect calls made through Apple CarPlay. The bulletin provides clear guidance for customers and technicians on how to mitigate or resolve this problem, ensuring better call clarity.

Symptoms

The primary symptom of this issue is a BMW X5 distorted voice (or distorted voice in other affected BMW models) heard by the person on the other end of a phone call. When making calls using the vehicle's BMW Bluetooth system, the audio received by the external caller is perceived as unclear or garbled. This distortion is consistent and occurs specifically when using an iPhone 14 or earlier model.

Cause of the Distortion

According to SIB 84 02 25, the root cause of this voice quality problem lies with iOS version 18.4. In this particular iOS release, the sound signal generated by affected iPhones is amplified by an additional 20 dB during Bluetooth telephony. This increased amplification, when compared to previous iOS versions, leads to audio distortions. Importantly, this issue is independent of the vehicle's BMW software version, meaning it can occur regardless of the car's internal software updates.

Repair Procedure Summary

The primary solution for this distorted voice issue, as outlined in BMW SIB 84 02 25, involves updating the iPhone's operating system. A fix has been integrated into iOS version 18.5.

1. Update iPhone Software: Customers should be instructed to update their iPhone software to iOS 18.5 or a newer version. This update contains the necessary correction to prevent the excessive audio amplification.
2. Activate "Voice Isolation" (If Update Not Possible): If updating the iPhone to iOS 18.5 or higher is not feasible, customers can utilize the "Voice Isolation" microphone mode on their iPhone. This feature is designed to reduce background noise and can help mitigate the distorted voice during phone calls.
   • To enable "Voice Isolation," first ensure the feature is added to your iPhone settings by navigating to "Settings > Accessibility > Audio & Visual > Add Voice Isolation."
   • Once added, during an active phone call, swipe down on the main call screen to access the iPhone Control Center. From there, select the "Phone Controls" option and then choose "Voice Isolation."
3. Use Apple CarPlay as an Alternative: If activating "Voice Isolation" does not sufficiently reduce the distorted voice reproduction, using Apple CarPlay for phone calls can serve as an effective alternative. This option is available via the vehicle's "All Apps" menu.

Important Warnings

Owners should be aware of several key points regarding this issue and its resolution:

• No Warranty Coverage: BMW SIB 84 02 25 explicitly states that "There is no BMW warranty coverage for this issue." This means any costs associated with troubleshooting or implementing these solutions would typically not be covered under warranty.
• "Voice Isolation" Activation: The activation of "Voice Isolation" must be performed during an ACTIVE phone call. Furthermore, BMW advises, "Do not perform this activation unless the vehicle is at a standstill." This ensures safety and proper configuration.

Owner Action

If you are experiencing a BMW X5 distorted voice or similar call quality issues in your 2024-2025 BMW vehicle with an iPhone 14 or earlier, the first step is to update your iPhone to iOS 18.5 or higher. If an update is not immediately possible, follow the steps to enable "Voice Isolation" on your iPhone. If these solutions do not resolve the problem, consider using Apple CarPlay for your phone calls. Since there is no warranty coverage for this issue, these steps can be performed by the owner without a dealer visit.

Source: NHTSA ID: 11018554