A Flashing Engine Light Stores a Code
Short answer: if the engine light is flashing, pull over when it is safe and read the code.
Plug the V310 lead into the 16-pin OBD-II port and turn the ignition on. Choose Read Codes, then View Freeze Frame.
After the fault is fixed
You can clear the code once the fault is fixed. If the fault is still there, the light can come back. I/M Readiness shows which monitors are complete.
Photos and the menu are on our V310 code reader page.