Diagnostic trouble code (DTC) information

Condition 

Diagnostic trouble code (DTC) AUM-4001 is stored if the ignition is on, main antenna supplied with power and the head unit/audio module detects low voltage on the main antenna output voltage.

Possible Source 

• The power supply from head unit to the main antenna is short-circuited to ground.
• Defective antenna amplifier

Fault symptom[s] 

• Poor radio reception (AM).