htc one x bluetooth carkit issue.

[bigmind]

Hi,
Guys I am having an issue in my htc one x version 4.0.3. while I am hooked up with my bluetooth carkit. I can't pick up calls and talk straight from my car's speakers . I have first to pick up from the phone and switch the speaker to htc speaker then I have to switch the phone to my car's speaker again. At this point the call is heard through the car's speakers. !! PLZ HOW CAN I FIX THIS ?? ??
This issue only happens on my phone. It doesn't show up while hooking iphone or any other htc.