Navigation Radio Displays No GPS Signal - keywords onstar UE1

This PI has been updated to enhance the Recommendations Field and add all models per conference call meeting with Onstar. Please discard PIT4118A.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Some customers may comment that when using the Navigation System the Navigation map is showing the incorrect location for the vehicle. After further diagnosis, you may notice that the Navigation Radio has no GPS signal which is indicated by a GPS indicator always present on the radio display. The concern may be caused by OnStar antenna overshadowing the GPS signal of the radio.

Disconnect the GPS antenna from the OnStar module. If the No GPS symbol disappears from the radio, replace the OnStar GPS antenna. Do not replace the radio or GPS antenna for the radio. If the No GPS symbol remains, follow normal diagnosis in SI2000.

Note: It is normal for the vehicle to display the No GPS symbol for up to 2 minutes when the vehicle is started or when the signal is obstructed by large/tall buildings or heavy foliage.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.