C1445 driving without initializing steering angle sensor

As far as I know, there is no manual calibration procedure for a steering angle sensor. If you view its reading on a scan tool when the car's just been turned on, it shows some bogus reading like -1300°. The reading updates to realistic as soon as you've driven straight for a bit, which the ECU can tell by the zero yaw sensor reading and the wheel speeds being equal. (So, this relies in part on the yaw sensor and there is a manual calibration for that, but probably of little interest unless someone has disturbed the yaw sensor.)

While I don't have easy access to the repair manual right now, this looks like probably the right C1445 details here.

The language there about "calibration cannot be obtained" does not suggest to me that there's any manual calibration step you've forgotten to do, and more that the car's normal automatic calibration hasn't worked out for some reason, such as the angle sensor not working right, or reporting a value that is off by more than the auto calibration process expects.

If there's been a recent change to the alignment or steering wheel centering, that repair manual excerpt does seem to suggest that relearning the yaw sensor zero point might help. There is a "when not using the Techstream" procedure for that, which involves jumpering a terminal ("TS", not the "TC" terminal that gets mentioned more often) to ground.