Diagnostic Trouble Code Information

Condition 

Fig 1: Identifying Water Pump

Courtesy of VOLVO CARS CORPORATION

If the water 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-5F3B will be set.

Substitute Value 

• None.

Possible Source 

• Contact resistance in control unit or water pump connector.
• Signal wire short-circuited to ground.
• Open circuit in voltage wire.
• Open circuit in signal wire.
• Defective water pump.

Fault symptom[s] 

• Parking heater does not work.
• Poor interior heating.