I've recently noticed that when stationary in drive and the steering wheel is turned slightly either left or right, the dash voltmeter drops 3-4 needle widths and then rises to a normal reading within 1-2 secs. If I turn the steering wheel almost to lock, the voltmeter drops to approx. battery voltage (just above the red warning bar). After several seconds, the needle slowly rises to a normal reading again (normal being 1-2 needle widths below 14 V). The car has the Magnasteer option. Any ideas as to the cause? Defective alternator or Magnasteer valve on the rack?

Not sure if it'* related, but I'm also getting DTC P0102. I've performed the following actions, all failing to fix the problem:
- cleaned battery cables
- sprayed carb cleaner on throttle body, egr pipe, brake booster hose, UIM, and LIM
- disconnected and plugged vac hose from throttle body to evap purge valve
- disconnected egr valve to eliminate possible vac leaks
- disconnected MAF sensor
- cleaned MAF sensor

I would check to make sure that the battery is in the best of health, and I would also want to make sure that you have proper belt tension, and the belt is not slipping.

To close this thread, it appears the problem was caused by a faulty mass airflow (MAF) sensor.

Based on what I've read in this and other forums, the PCM cuts off the alternator field current below a certain engine RPM. The idle speed, at times, was low to begin with due to the defective MAF sensor, and turning the wheel caused a further drop in rpm due to the drag of the pump, resulting in low alternator output voltage.