What Data is Available from OBD?
OBD-II offers a standard way to access many types of data, including:
- Real-time parameters: RPM, speed, pedal position, spark advance, airflow rate, coolant temperature, etc.
- Status of “Check Engine” light
- Emission readiness status
- Freeze frame: a “snapshot” of parameters at the time a trouble event has occurred.
- Diagnostic trouble codes (DTCs).
- Oxygen sensor test results
- Vehicle Identification Number (VIN)
- Number of ignition cycles
- Number of miles driven with MIL on
The SAE J1979 standard is the ultimate source for this information. Some of it is available for free from Wikipedia.