Diagnostic Trouble Code (DTC) Information ECM-2840

Condition 

Fig 1: 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 pump current has ceased and the front heated oxygen sensor (HO2S) signal has been set to a default value.

Substitute Value 

None.

Possible Source 

• Contact resistance and oxidation in the terminals
• Open-circuit in the cable for pump current
• Damaged front heated oxygen sensor (HO2S).

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit.