What are the reasons for the engine warning light in XC60?

[StEverly]

Sensor issues, car maintenance problems, fuel quality issues, poor combustion of the air-fuel mixture, engine intake problems, turbocharging issues, exhaust problems, and anti-theft system malfunctions are the main reasons that cause the engine warning light to illuminate. Additionally, when starting the car, the vehicle performs a self-check on the engine system. Normally, the engine warning light will turn off after the self-check is completed. If it remains on for an extended period, you should promptly visit a repair shop to seek professional help and eliminate potential safety hazards. Here are detailed explanations for each type of fault: Sensor problems: Sensors include coolant temperature, crankshaft position, air flow, intake temperature, oxygen sensors, etc. When these sensors are damaged, have poor contact, or experience signal interruptions, the car's ECU cannot accurately obtain engine data, which will cause the engine warning light to illuminate. In such cases, you should promptly visit a repair center for professional inspection to eliminate safety hazards. Maintenance issues: Poor engine maintenance is the most common cause of the engine warning light. Vehicles have specific maintenance cycles. If maintenance is not performed on schedule, combined with poor driving habits, the engine's operational burden will increase, eventually causing the engine warning light to illuminate as a reminder of a fault. Fuel quality issues: This refers to both fuel and engine oil. The fuel used in cars usually has a specific grade, and engine oil can be semi-synthetic or fully synthetic. Manufacturers typically recommend which fuel grade and oil type to use. If the owner does not follow these recommendations, long-term use can lead to engine wear, triggering the warning light. Always use the recommended fuel grade and engine oil for your vehicle. Poor combustion of the air-fuel mixture: Faulty spark plugs, ignition coils, fuel pumps, or clogged fuel lines can cause poor combustion of the air-fuel mixture. This leads to engine carbon buildup or knocking, which the oxygen sensor detects and reports to the ECU, resulting in the warning light illuminating as a warning. Intake problems: The engine requires air for combustion, and the air filter plays a crucial role. If the air filter is dirty or not cleaned regularly, it can affect the engine's air intake. Over time, this can lead to blockages, and in severe cases, the engine warning light may illuminate. Turbocharging issues: Problems with the intake turbocharging pipeline or turbocharger can also cause the engine warning light to illuminate. The most common issue is a damaged turbocharger, accompanied by symptoms such as oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Exhaust problems: Faults in the rear oxygen sensor, catalytic converter, exhaust camshaft, or bearings can trigger the engine warning light. The most common issue is a faulty catalytic converter. Factors such as using leaded gasoline, lead or silicon-based oil additives, physical damage to the catalytic converter, or fuel system malfunctions can easily cause catalytic converter failure. Anti-theft system: If the car's electronic anti-theft system malfunctions or the anti-theft controller does not match the engine ECU, the anti-theft system can prevent the engine from operating normally, and the engine warning light will illuminate. When the engine is unstable, check the following: Inspect the spark plugs and ignition wires. Test the fuel pressure system. Check each cylinder's fuel injector. Inspect the fuel pump and its circuit. Check cylinder pressure, intake and exhaust valve clearance, fuel vapor control solenoid valve, EGR valve operation, and intake manifold leaks. There are many reasons for engine instability, so it's important to visit a service center for a thorough inspection to accurately identify and resolve the issue. Solutions for the engine warning light: If the engine warning light is on and the car won't start, this may be due to a faulty fuel pump or ignition components. Call for assistance immediately. If the engine warning light is on and the car can still be driven but exhibits severe shaking or loss of acceleration, pull over and call for help. If the engine warning light is on but there are no noticeable driving issues, it may be due to a faulty sensor. You can continue driving cautiously at low speeds but should visit a repair shop as soon as possible to eliminate safety hazards.

[McJonathan]

I also drive an XC60, and that engine malfunction indicator light coming on is truly nerve-wracking. The most common causes are exhaust system issues, such as aging oxygen sensors or clogged catalytic converters—these components control emissions and tend to trigger false alarms due to carbon buildup over time. Next, ignition system problems like excessive spark plug gaps or faulty coils, as well as poor fuel quality, often activate the light. Sometimes it's minor—like a loose fuel cap or low engine oil—so checking basic fluids first is wise. The most reliable approach, in my opinion, is investing in a Bluetooth OBD scanner (just tens of dollars) to read trouble codes. If it's a sensor-related code, cleaning might resolve it. Never delay, especially if the light flashes—stop driving immediately to avoid engine damage. A full diagnosis at the dealership is the safest bet, given the safety implications.