A problematic center airbag sensor can cause the airbag malfunction light to illuminate.
2008 Toyota Highlander Problem Reports
Most Reported 2008 Toyota Highlander Problem Reports
The Check Engine Light may illuminate because a component of the oxygen sensor stops working. As a result the engine computer is unable to determine the proper ratio of air to fuel for the engine. Replacing the failed oxygen sensor should correct this concern.
On higher mileage vehicles, an engine misfire may develop and/or the Check Engine Light may illuminate due to a failed ignition coil. It is not uncommon to replace all the coils when the first one fails in order to prevent return trips to the repair shop.
When changing the air filter, it is easy to knock off a hose on the air filter housing, which is part of the emission control system. If the vehicle is driven with this hose disconnected, the Check Engine Light will illuminate.