Faulty oxygen sensors, hybrid battery sensors, or inverters can miscommunicate with the Electronic Control Unit (ECU) , leading to a system-wide alert.
The specific cause often depends on which XC90 powertrain you own. The XC90 has seen various iterations, including the older 5-cylinder engines, the modern Drive-E 4-cylinder engines, and the Twin Engine (T8) Plug-in Hybrids. volvo propulsion system service required xc90
The lesson: Diagnose thoroughly. The second fault was hidden by the first. Faulty oxygen sensors, hybrid battery sensors, or inverters