DTC B0020-12: Left Side Airbag Deployment Control - Circuit short to battery: Action

NOTE: When the airbag connector is DISCONNECTED if the locking plunger can move to the locked position easily (reasonable pressure) the connector is damaged

Visually inspect the left side airbag connector, the locking plunger should be flush with the housing. If not, push the locking plunger in. Clear the Diagnostic Trouble Code(s) and retest
If problem still persists, disconnect and reconnect all connectors. Also test connectors (see above note). Clear the Diagnostic Trouble Code(s) and retest
Refer to the electrical circuit diagrams and check the left side airbag (seat) circuit for short circuit to power. Repair the circuit as necessary, clear the DTC and retest