ELM327 Bluetooth supports all OBD-II protocols
ISO15765-4 (CAN)
ISO14230-4 (KWP2000)
ISO9141-2
J1850 VPW
J1850 PWM

Function:
Read diagnostic trouble codes, both generic and manufacturer-specific, and display their meaning (over 3000 generic code definitions in the database). Clear trouble codes and turn off the MIL ("Check Engine" light)
Display current sensor data, including:
Engine RPM    
Calculated Load Value
Coolant Temperatur      
Fuel System Status
Vehicle Speed    
Short Term Fuel Trim
Long Term Fuel Trim      
Intake Manifold Pressure
Timing Advance      
Intake Air Temperature
Air Flow Rate      
Absolute Throttle Position
Oxygen sensor voltages/associated short term fuel trims    
Fuel System status
Fuel Pressure    
Upcoming Features:
Data graphing and logging                  
Freeze Frame data
Continuous and Non-Continuous Oxygen Sensor test results    
Many others...