"Front Left Sensor Output Too Low" would tend to suggest a problem developing with the speed sensor on the front nearside wheel. It might be due to the sensor itself having been disturbed and consequently not sitting in its correct position or a fault starting in the plug and wiring.
The first things to check, after clearing the historic faults would be that the sensor is securely in place and then that the plug where the sensor lead connects to the vehicle wiring is clean.
Then take the vehicle for a short drive and recheck the codes. The action of unplugging and reconnecting the sensor wiring might even clear the faults, if you're lucky.
These sensors send a signal proportional to each wheel speed to the SLABS ECU which allow "electronic decisions" to be made by the ECU about engaging ABS, Traction control or hill descent control, as required.
What, if any dashboard lights do you have showing?