Rear heated oxygen sensor (HO2S), electronic check
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Volvo S80, 2005 Volvo S80, 2004 Volvo S80, 2003 Volvo S80, and 2002 Volvo S80. However, it is still accessible from the selected car via links, so may be relevant.
Diagnostic trouble code (DTC) ECM-2A0A/2B0A is stored if there is a fault in the rear heated oxygen sensors (HO2S) or its wiring causing the signal to deviate from its permitted value.