Diagnostic Trouble Code (DTC) Information ECM-2A2A

Condition 

Fig 1: Identifying Rear 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 of the rear heated oxygen sensor (HO2S) in the pre-heating circuit is too high for a certain amount of time.

Substitute Value 

None.

Possible Source 

• Contact resistance or oxidation in the terminals
• Damaged rear heated oxygen sensor (HO2S).

Fault symptom[s] 

• Malfunction indicator lamp (MIL) lit.