Diagnostic trouble code information

Condition 

Fig 1: Identifying Fuel Pump

Courtesy of VOLVO CARS OF NORTH AMERICA.

If the fuel pump circuit is short-circuited to ground or if there is an open circuit, the control unit will interpret this as a fault, and diagnostic trouble code CEM-5F40 will be set.

Substitute Value 

• None.

Possible Source 

• Contact resistance in control unit or fuel pump connector.
• Signal wire short-circuited to ground.
• Open circuit in signal wire.
• Open circuit in voltage wire.
• Damaged fuel pump.
• Damaged overheat protection thermostat.

Fault symptom[s] 

• Poor interior heating.