These are past discussions on LED headlamps:
www.200forums.com
Unless lamps are DOT-approved/certified/compliant & meet FMVSS 108, they may not be street-legal.
The BCM looks for a range of current draw for both the Halogen & HID headlamps. If the current draw is over or under the limits, the circuit can be disabled & a fault code stored in the BCM. Headlamps can blink, flicker or shut-off.
You will likely have to add a pair of parallel resistors to fool the BCM, at least. Currently AFAIK, there is no legal aftermarket solution for 'public highway use' LED conversions:
A lot of what I read on the internet is confusing/conflicting about this, much of it seems to be sponsored by or written by LED headlamp marketers. Check your federal, state (DMV) & local motor vehicle lighting laws.