Diagnostic Trouble Code (DTC) Information CEM-9F31

Condition 

Fig 1: Identifying Rheostat

Courtesy of VOLVO CARS OF NORTH AMERICA.

The diagnostic trouble code (DTC) is stored if the central electronic module (CEM) registers that the signal is too high or that there is no input signal from the rheostat.

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

Substitute Value 

• None.

Possible Source 

• Short-circuit to supply voltage in the rheostat
• Open-circuit in the signal cable
• Damaged light switch.

Fault symptom[s] 

• The instrument lighting does not operate
• The instrument lighting is constantly lit at full strength.