I was parked my car on a slope, nose pointed down the slope, went into neutral, engaged parking break, then geared into Park. Then tried to lower car into access mode, but it would not lower entirely. Came back 3 hours later, and computer said car was in EXTENDED MODE. Tried to change suspension height, but the front would not go up, just got stuck in access height while rear suspension went up to normal.....everything went back to normal after a while of driving. Is this normal?

Is it possible there was something under the car stopping it going into Access Mode? If so, and the computer therefore senses that the vehicle is grounded, the air suspension will go into 'Extended Mode' which is actually above Off-Road height - so trying to raise it would achieve nothing! On driving off, it will quickly return to Off-Road height and then lower to Normal at above 30 mph.

HTH.