Diagnostic trouble code information

SWM-0021 

Condition 

Fig 1: Identifying Audio Control Scan-Button

Courtesy of VOLVO CARS OF NORTH AMERICA.

If SWM microprocessor/control unit registers that Scan- control is activated for more than 5 minutes, diagnostic trouble code SWM-0021 is displayed.

Substitute Value 

Nothing.

Possible Source 

• Scan- control is activated for more than 5 minutes.

Fault symptom[s] 

• Station settings change without scan+ or scan- buttons being activated manually
• Radio steering wheel buttons do not work
• Telephone not working.