Diagnostic trouble code (DTC) information CEM-5A00

Condition 

Fig 1: Identifying Twilight Sensor

Courtesy of VOLVO CARS OF NORTH AMERICA.

The central electronic module (HEM) checks the signal from the sun sensor.

The diagnostic trouble code (DTC) is stored if the central electronic module (HEM) registers that the signal from the sensor is too high.

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

Substitute Value 

• The control module adopts a substitute value corresponding to approximately 20% (200 W/m² ) of maximum solar heat.

Possible Source 

• Short-circuit to supply voltage in the signal cable between the control module and the sun sensor
• Damaged sun sensor.

Fault symptom[s] 

• The passenger compartment temperature does not drop when the sun intensity is high.