Diagnostic trouble code (DTC) information CEM-4A31

Condition 

Fig 1: Identifying Fuel Pump

Courtesy of VOLVO CARS OF NORTH AMERICA.

The central electronic module (CEM) continuously checks the signal from the sensor on the ejector side which indicates the level in one of the fuel tanks.

The diagnostic trouble code (DTC) is stored if the central electronic module (CEM) detects that the fuel level has not changed during the last 100 km.

The diagnostic trouble code (DTC) can be diagnosed with the ignition on and the fuel level above 2 liters.

Substitute Value 

• None.

Possible Source 

• The sensor on the ejector side is faulty.

Fault symptom[s] 

• The trip computer displays an empty fuel tank too early.
• The fuel gauge indicates zero even though there is fuel in the tank.