Diagnostic trouble code (DTC) information ECM-250C

Condition 

Fig 1: Identifying Front Heated Oxygen Sensor

Courtesy of VOLVO CARS OF NORTH AMERICA.

The diagnostic trouble code (DTC) is stored if the engine control module (ECM) registers that the resistance in the preheating circuit for the front heated oxygen sensor (HO2S) (bank 2) is too high.

Substitute Value 

• None.

Possible Source 

• Contact resistance and oxidation in the terminals
• Damaged front heated oxygen sensor (HO2S).

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit.