Sorry for the delay. I had a little "emergency" here at home.
You should be OK to drive (it should NOT be unsafe), but it should be looked into. Here are a couple of things I found in the service manual.
The first is a technical bulletin about this issue. The second is a troubleshooting chart that has to do with these symptoms. The second is a PDF file that you should be able to view on your computer and print if needed.
ABS and/or Traction Control Lamp On, AWD Disabled Message Displayed, DTCs Set (Replace Front Wheel Bearing and Hub Assembly) #03-05-25-004A - (Apr 14, 2004)
ABS and/or Traction Control Lamp On, AWD Disabled Message Displayed, DTCs Set (Replace Front Wheel Bearing and Hub Assembly)
2002-2004 Buick Rendezvous
2002-2004 Chevrolet Venture
2002-2004 Oldsmobile Silhouette
2002-2004 Pontiac Aztek, Montana
with All Wheel Drive
This bulletin is being revised to change part number information and update the model years. Please discard Corporate Bulletin Number 03-05-25-004 (Section 05 -- Brakes).
Some customers may comment that the ABS and/or traction control system lamp is illuminated. Also, the AWD disabled message may be displayed. Upon investigation, the technician may find several DTCs set.
When normal diagnosis leads to the wheel speed sensor as the suspect component, replace the front wheel bearing and hub assembly, P/N 89047684. Refer to the Wheel Bearing/Hub Replacement procedure in the Front Suspension sub-section of the Service Manual. This new part has 6 mm (0.236 in) added to the harness to prevent any stress to the wiring.
AWD Disabled Always ON
I hope this helps.
Take Care, Greg A.