A control system for a vehicle powertrain having an engine and at least one turbocharger, the system comprising: an exhaust oxygen sensor configured to measure an O2 concentration of exhaust gas generated by and expelled from the engine into an exhaust system; and a controller configured to operate the engine in a scavenging mode, where opening of respective intake and exhaust valves (144,148) of cylinders of the engine overlap, and while the operating the engine in the scavenging mode: command a target in-cylinder air/fuel ratio for achieving a target exhaust gas air/fuel ratio; receive from the exhaust oxygen sensor, a measurement of an O2 concentration of exhaust gas generated by and expelled from the engine into the exhaust system; adjust the measurement of the exhaust O2 sensor based on a scavenging ratio and the target in-cylinder air/fuel ratio to obtain a modified O2 concentration, the scavenging ratio indicating a ratio of (i) a total air charge flowing through a cylinder of the engine to (ii) a trapped air mass within the cylinder; adjust an exhaust system temperature modeled by a thermal model to obtain a modified exhaust system temperature, the adjustment to the modeled exhaust system temperature being based on the scavenging ratio and at least one of the target in-cylinder air/fuel ratio and the target exhaust gas air/fuel ratio; and adjust the target in-cylinder air/fuel ratio based on the modified O2 concentration and the modified exhaust system temperature. an exhaust oxygen sensor configured to measure an O2 concentration of exhaust gas generated by and expelled from the engine into an exhaust system; and a controller configured to operate the engine in a scavenging mode, where opening of respective intake and exhaust valves (144,148) of cylinders of the engine overlap, and while the operating the engine in the scavenging mode: command a target in-cylinder air/fuel ratio for achieving a target exhaust gas air/fuel ratio; receive from the exhaust oxygen sensor, a measurement of an O2 concentration of exhaust gas generated by and expelled from the engine into the exhaust system; adjust the measurement of the exhaust O2 sensor based on a scavenging ratio and the target in-cylinder air/fuel ratio to obtain a modified O2 concentration, the scavenging ratio indicating a ratio of (i) a total air charge flowing through a cylinder of the engine to (ii) a trapped air mass within the cylinder; adjust an exhaust system temperature modeled by a thermal model to obtain a modified exhaust system temperature, the adjustment to the modeled exhaust system temperature being based on the scavenging ratio and at least one of the target in-cylinder air/fuel ratio and the target exhaust gas air/fuel ratio; and adjust the target in-cylinder air/fuel ratio based on the modified O2 concentration and the modified exhaust system temperature. command a target in-cylinder air/fuel ratio for achieving a target exhaust gas air/fuel ratio; receive from the exhaust oxygen sensor, a measurement of an O2 concentration of exhaust gas generated by and expelled from the engine into the exhaust system; adjust the measurement of the exhaust O2 sensor based on a scavenging ratio and the target in-cylinder air/fuel ratio to obtain a modified O2 concentration, the scavenging ratio indicating a ratio of (i) a total air charge flowing through a cylinder of the engine to (ii) a trapped air mass within the cylinder; adjust an exhaust system temperature modeled by a thermal model to obtain a modified exhaust system temperature, the adjustment to the modeled exhaust system temperature being based on the scavenging ratio and at least one of the target in-cylinder air/fuel ratio and the target exhaust gas air/fuel ratio; and adjust the target in-cylinder air/fuel ratio based on the modified O2 concentration and the modified exhaust system temperature.