P0102

A code P0102 may mean that one or more of the following has happened:

The MAF may be disconnected, or a wiring connection may be bad
The MAF may be dirty or otherwise contaminated (Note: if you use a reusable oiled air filter, be careful not to apply too much oil or that can contaminate the MAF).
The MAF sensor may be faulty
The vehicle computer may be faulty (very rare)
Possible SolutionsThe simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures:

Verify that the Mass Air Flow Sensor wiring is connected properly and that there are no broken / frayed wires.
Inspect for any air leaks near the MAF sensor.
Take the MAF out and clean it using a spray cleaner such as brake cleaner or electrical contact cleaner. Be gentle with the sensor.
Check the voltage of the MAF sensor (refer to a repair manual for vehicle specific information)