For 1990-2009 cars

If the vehicle has this feature, engine power is sent to all four wheels when extra traction is needed. This is like four-wheel drive, but there is no separate lever or switch to engage or disengage the axle. It is fully automatic, and adjusts itself as needed for road conditions.

When using a compact spare tire on the AWD equipped vehicle, the AWD system automatically detects the presence of the compact spare and the AWD is disabled. To restore the AWD operation and prevent excessive wear on the AWD system, replace the compact spare with a full-size tire as soon as possible. See Compact Spare Tire for more information.