This warning light illuminates:
NOTICE
- Malfunction Indicator Lamp (MIL)
Driving with the Malfunction Indicator Lamp (MIL) on may cause damage to the emission control systems which could affect drivability and/or fuel economy.
NOTICE
If the Malfunction Indicator Lamp (MIL) illuminates, potential catalytic converter damage is possible which could result in loss of engine power.
In this case, have your vehicle inspected by an authorized HYUNDAI dealer.
Hyundai Sonata LF 2014-2019 Service Manual: Speaker Repair procedures
Inspection
1.
Troubleshooting for Speaker
(1)
Basic inspection of speaker
Inspect the sound from speaker after verifying that the
speaker mounting screws is removed and the wiring connector is connected
precisely to remove vibration transmitted from body trims and
surrounding parts.
...
Hyundai Sonata LF 2014-2019 Service Manual: Components and Components Location
Components
1. Rear window glass2. Rear glass lower moulding
...