Which of the following can cause the Check Engine light to illuminate?

Sensor malfunctions are a common cause for the Check Engine light to illuminate because modern vehicles rely on a variety of sensors to monitor various systems, such as the engine, exhaust, fuel, and emissions. These sensors send data to the vehicle's onboard computer, which diagnoses the performance of these systems. If a sensor is malfunctioning or providing inaccurate readings, the computer may detect an issue that requires attention, thereby triggering the Check Engine light as a warning to the driver.

Other options, while they can affect vehicle performance, do not typically lead to the illumination of the Check Engine light. For instance, low fuel levels may indicate that the tank needs refilling, but it usually does not activate the Check Engine light specifically. Using synthetic oil is related to engine lubrication and performance but does not directly correlate with triggering a warning light. Installing new tires primarily impacts traction and handling rather than the engine’s performance or emissions, which are what the Check Engine light is designed to monitor.