| Subject: | Information On Noise Sources From Navigation Radio - CD/DVD Disc Accessing Noise From Radio Fan, For Cooling, Disc Accessing Noise for Navigation Operation Or NAV Traffic Information |
| Models: | 2008-2009 Buick Enclave |
| 2007-2009 Cadillac DTS, Escalade, Escalade ESV, Escalade EXT, SRX |
| 2007-2009 Chevrolet Avalanche, Silverado, Suburban, Tahoe |
| 2007-2009 GMC Acadia, Sierra, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL |
This bulletin is being revised to add models, additional characteristics and diagnostics. Please discard Corporate Bulletin Number 06-08-44-034B (Section 08 -- Body and Accessories).
Some customers may comment that there is unusual fan type noises coming from the navigation radio. Additionally , customers may comment on Radio noise coming from the CD/DVD or MAP Disc mechanisms when CDs/DVDs or MAP discs are present in the CD mechanisms.
Some customers have mentioned that radio noise is present when the customer enters the vehicle or that the noise continues after they shut the vehicle off and open the door to leave the vehicle. This noise has been described as a fan sound or hearing a disc
spinning.
Source of fan sound -- It is normal for the radio fan to run when the vehicle is turned on and for up to three minutes after the vehicle has been turned off and the driver's door has been opened or closed.
Disc spinning sound -- This is a normal operational sound. This is caused by the map disc spinning behind the tilt screen. It is a normal operation after the RKE is used to unlock the vehicle or when the driver's door has been opened. This noise will
also be heard during vehicle operation and up to three minutes after the vehicle has been turned off and driver's door has been opened and closed.
MAP Disc Accessing "ZIP" sound -- As the Navigation Radio accesses the MAP Disc, the customer may describe frequent "zip" type noises. This noise is caused by the CD Read Lens moving across the disc to access needed data for
proper MAP display. To determine if the source of the noise is from accessing the MAP Disc, remove the MAP Disc to determine if the noise continues. With the addition of the Real Time NAV Traffic Feature, the MAP CD may be accessed to a greater extent thus resulting
in additional MAP Drive noise.
Educate the customer about these noises. If the customer believes the noise is not normal, compare the condition to a like vehicle with identical settings to determine if there is a noticeable difference.
Do not replace the radio as the described conditions are normal operating characteristics.
