Diagnostic Trouble Code (DTC) Information ECM-249B

Condition 

Fig 1: Front Heated Oxygen Sensor

Courtesy of VOLVO CARS CORPORATION

The diagnostic trouble code (DTC) is stored if the engine control module (ECM) registers an open-circuit in the signal cable to the component of the front heated oxygen sensor (HO2S) that detects the oxygen content of the exhaust gases.

Substitute Value 

None.

Possible Source 

• Contact resistance or oxidation on the signal cable
• Open-circuit in the signal cable
• Damaged front heated oxygen sensor (HO2S).

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit.