Some car stereos require a firmware update for AVRCP 1.4 Bluetooth compatibility

Symptoms

Some car stereos and accessories that use Bluetooth for control and playback may require a firmware update to work as expected with the AVRCP 1.4 support added in iOS 6.

Symptoms may include:

• Unable to control playback through Bluetooth
• Song name, artist, and other information is not displayed on the car stereo

Resolution

iOS 6 supports AVRCP 1.4, the latest Bluetooth standard for control and playback. Your car stereo (sometimes called a head unit) may require a firmware update to correctly support the Bluetooth standard.

Several manufacturers, including Advent and Pioneer, have announced plans to provide an update or already have one available. Please contact your car stereo manufacturer to see if a firmware update is available.

Additional Information

The following is a partial list of affected car stereos:

• Advent OE Multimedia Headunits
• Alpine CDE-133BT
• Alpine CDE-135BT
• Alpine CDE-136BT
• Alpine CDE-HD137BT
• Alpine CDE-HD138BT
• Alpine CDE-W235BT
• Alpine IVE-W530
• Clarion CZ702
• Clarion CZ302
• Clarion FZ502
• Clarion M502
• Clarion NX602
• Clarion NX702
• Kenwood DNX6190HD
• Kenwood DNX6990HD
• Kenwood DNX7190HD
• Kenwood DNX9990HD
• Kenwood KDC-BT752HD
• Kenwood KDC-BT852HD
• Kenwood KDC-BT952HD
• Kenwood KDC-X796
• Kenwood KDC-X896
• Kenwood KDC-X996
• Pioneer DEH-P8400BH
• Pioneer DEH-P9400BH
• Pioneer DEH-80PRS
• Pioneer AVH-P2400BT
• Pioneer AVH-P3400BH
• Pioneer AVH-P4400BH
• Pioneer AVH-P8400BH

Find information on troubleshooting car stereo connections.

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Source : http://support.apple.com/kb/TS4483