What Causes the X-Trail's Warning Light to Illuminate?

[StMila]

The reasons for the X-Trail's warning light illuminating are as follows: 1. Poor or substandard gasoline quality: This usually occurs after refueling at non-standard gas stations with low-quality gasoline, leading to insufficient combustion of the air-fuel mixture during engine operation and triggering the engine warning light. While this doesn't affect driving safety, it may cause some degree of harm to the engine. 2. Oxygen sensor malfunction: Modern vehicles are equipped with two oxygen sensors, one before and one after the three-way catalytic converter. The front oxygen sensor detects the air-fuel ratio under different engine operating conditions, while the ECU adjusts fuel injection and calculates ignition timing based on this signal. The rear sensor primarily monitors the performance of the three-way catalytic converter. Therefore, damage to the oxygen sensor or issues with the sensor connector (such as damage or looseness) can result in an overly lean or rich air-fuel mixture, causing the warning light to illuminate.