Diagnostic Trouble Code (DTC) Information CEM-8A21

Condition 

Fig 1: Identifying Right-Hand Gas Discharge Lamp Module

Courtesy of VOLVO CARS OF NORTH AMERICA.

The central electronic module (CEM) communicates with the left-hand gas discharge lamp module (GDL).

The diagnostic trouble code (DTC) is stored if the central electronic module (CEM) receives information from the left-hand gas discharge lamp module (GDL), which registers that the position sensors are not calibrated.

The diagnostic trouble code (DTC) can be diagnosed when the ignition is switched on.

Substitute Value 

• The shortest headlamp range will be used.

Possible Source 

• The position sensors are not calibrated.

Fault symptom[s] 

• Automatic headlamp range control is not functioning.