Subject: | Information On Navigation Radio Not Displaying Accurate Vehicle Location After Radio Replacement, Power Loss Or Battery Replacement |
Models: | 2009 and Prior GM Passenger Cars and Trucks (Including Saturn) |
| 2009 and Prior HUMMER H2, H3 |
The purpose of this bulletin is to inform technicians and customers that the Navigation Radio may not display the vehicle location icon on the map accurately after a radio or battery has been replaced or after battery power has been removed from the radio.
The vehicle location icon accuracy may be degraded if the GPS signal is not available and the GPS displayed icon has a red line through it.
The Navigation Radio does not keep learned GPS information or gyroscope and vehicle speed signals stored when the battery power is removed from the radio. The Navigation radio continually uses GPS, gyroscope and vehicle speed data to maintain the vehicle
location icon positioned accurately on the displayed map. There may be periods of time during a drive cycle when the GPS signal may not be available and the vehicle location icon still appears to be accurate. This is due to the radio having internal gyroscopes
and receiving a vehicle speed signal to maintain accuracy if the radio had received a good GPS signal earlier in the drive cycle.
Normal driving will improve the accuracy of the vehicle location icon on the displayed map. It may be necessary for the vehicle to be driven up to 40 km (25 mi) with 15 left and 15 right turns while the vehicle location icon is matched to
roads on the displayed map. Do not replace the radio for this condition.