2006 530xi steering wheel does not unlock or start, with no 'steering lock error'

[greglox]

When the key FOB is inserted, the key is locked in place and the radio and the 'ignition 1' part of the dash comes on (time/date display is on, airbag and parking lights are on, odometer is on if I press the lower stalk button). The steering wheel is not unlocked (can't remember if it normally is at this point). When the START button is pressed, no more dash lights come on and the steering wheel is still locked...and, of course, the car does not start. I have *not* gotten the Steering Wheel Locked icon or any message regarding that. As the driver hung out in the car until I got there, the battery had depleted a bit and I have gotten the 'Increased Battery Discharge' message on the center display.

I have jumped the car for an hour and that didn't help. I have replaced the battery and that didn't help. I have pressed the START button for 30 seconds, didn't help. I have pressed both the brake and the clutch while pressing START, didn't help.

I'm waiting for a tow truck to bring the car to my mechanic (non-dealership, but BMW knowledgeable)

Any thoughts?

2006 530xi E60, manual transmission

[greglox]

Turns out to be the IBS (Intelligent Battery Sensor). Looking at IBS fault videos on YouTube, the symptoms are accurate, but it was difficult to get to an IBS fault diagnosis through my searches. The mechanic unplugged it and it allowed it to start (there is a video regarding unplugging it too).

Hopefully this posts helps.