We have encountered several reports with Hyundai/Kia OEM radio making a “squealing” noise when mobile phones and MP3 players are connected to the factory iPod/USB auxiliary inputs. Followed by this noise, symptoms may include but not limited to:

- CD being stuck in the loader or ‘Mecha error’ message

- Random Bluetooth commands (‘Phone not connected’, ‘Please pair phone’)

- Volume control moving up/down automatically

- No sound from AM/FM with SEEK button not being able to detect radio channels

- Audio mode automatically switching around

UNAVI has gone through extensive testing to determine the cause of this phenomenon and have made modifications to our components consequently in addressing some of the issues listed above.  According to our technical support data and experiences, it appears to be prevalent on the 2011-12 Hyundai Tucson particularly with the iPhone 4, iPhone 4S and iPad 2 using Hyundai’s iPod accessory cable.  (Note: regular USB cable will only work with 2012 Hyundai Sonata and 2012 Hyundai Veloster)

For your reference: List of compatible phones tested to work in Hyundai vehicles

While we initially assumed it was mainly our system that was causing the problem, this squealing noise also appeared on different Hyundai models without UNAVI installed. Several auto forums, blogs and Apple’s online discussion board have reported various issues with the Apple devices in general; however, the iPhone 4/4S seemed to be dominant among the issues reported by end users. In a broader sense this technical bulletin is not specific towards Apple product or even the iOS for that matter – it can also be caused when other devices are plugged in via USB such as the Blackberry and Android phones. 

There is no question that the UNAVI system can affect the voltage, RF signals, or EMI to the applicable vehicles where individually these vehicles may behave differently in terms of sensitivity levels, especially the voltage output from our components to the factory radio.  That being said, we suggest the following procedures to try when this problem is present with UNAVI installed:

• Add GROUND wire from the radio brain to vehicle chassis frame
• Try streaming music through Bluetooth on audio AUX mode (if applicable)
• Test whether the problem occurs with other phones or MP3 players
• Request the dealership to have the factory radio replaced under warranty and to see if the same problem persists

To a vehicle manufacturer’s defense, any aftermarket system is the culprit when situations like these arise – and their solution is to “simply remove it”.  As far as UNAVI is concerned, neither Hyundai nor Apple have publicly announced these problems and/or solutions. For further questions and troubleshooting details, please contact our Technical Support team at 855-558-6284.