Some users have informed us that when using the black Fujitsu head unit with the BT Changer module, the music occasionally fades out and then comes back after approximately 14 seconds. The playback on the phone continues without interruption, so it was clear that the head unit was responsible for the volume reduction.
We conducted extensive investigations into the root cause of the issue, which was challenging initially because it did not occur for us at first. Eventually, one of our test head units consistently exhibited this behavior, not only with the BT Changer but also with the original XM satellite receiver. After running numerous tests, we finally determined that the issue lies within the head unit’s software. Specifically, it is related to the FM channel’s Traffic Programme (TP) option, even when the XM radio channel is in use.
If the TP is enabled for a programmed FM radio channel, and the car goes out of the reception area while the head unit is in XM mode, it randomly lowers the volume of the music (as if transmitting a traffic announcement). This issue only arises when FM reception is weak or when there is a problem with the car’s antenna system.
The solution is straightforward.
You need to disable the TP option for the a tuned/programmed FM radio channel. After doing so, when you switch to XM mode, there will be no issues. Turning TP off will ensure that the BT Changer functions perfectly.
TP ON
TP OFF
Steps:
- Tune in to an FM radio channel with good reception.
- Turn off the TP option.
- Switch to XM mode.
- Random volume reduction does not occur when using BT Changer
Even poor FM signal can cause this.
Our own experiences have shown that in certain cases, even with the TP (Traffic Program) turned off, the issue can arise. This occurs when, for some reason, FM radio signal is unsatisfactory. It could be influenced by geographical location, weak radio signals, or problems with the car’s antenna or antenna amplifier. In such cases, it’s worth checking the FM antenna connections. However, if the FM radio transmission is weak, there’s not much we can do about it.
For example, I live in a town near a big city where hills obstruct good FM signal. When I start to drive with my 9-3, the music fades out once or twice along the way. But as soon as I reach the outskirts of the city (where several strong FM radio transmission), the problem never occurs again.
Unfortunately, the issue lies in the software of the factory head unit. The principle is that if FM transmission is weak, it attenuates the audio to reduce noise. This is fine, but it’s unreasonable for it to also mute the XM channel signal in case of poor FM reception.