What Causes the Engine Malfunction Light to Flash Continuously?

[DiBrandon]

When the engine malfunction light flashes, it indicates a serious engine issue that requires immediate inspection. Here are 7 potential causes: Sensor Failure: This includes sensors such as coolant temperature, crankshaft position, air flow, intake temperature, and oxygen sensors. If these sensors are damaged, have poor connections, or signal interruptions, the vehicle's ECU cannot accurately obtain engine data, triggering the malfunction light. Fuel/Oil Quality Issues: Using fuel or oil that does not meet manufacturer specifications may cause engine wear, leading to the malfunction light activation. Poor Combustion of Air-Fuel Mixture: Incomplete combustion can result in engine carbon buildup or knocking. When detected by the oxygen sensor and reported to the ECU, the malfunction light will illuminate as a warning. Causes include faulty spark plugs, ignition coils, fuel pump issues, or clogged fuel lines. Turbocharger Problems: Issues with the intake boost system or turbocharger can trigger the engine light. Common symptoms of turbocharger failure include oil leaks, excessive oil consumption, reduced power, metallic noises, or blue/black smoke from the exhaust. Intake System Issues: Clogged engine intake passages can cause the malfunction light to illuminate, often due to a dirty or unmaintained air filter. Exhaust System Problems: Exhaust-related faults such as rear oxygen sensor failure, catalytic converter issues, or exhaust camshaft and bearing wear can activate the light. The catalytic converter is particularly vulnerable to leaded gasoline, improper lubricant additives, physical damage, or fuel system malfunctions. Anti-Theft System Malfunction: If the vehicle's electronic anti-theft system fails or doesn't properly communicate with the engine control unit, it may prevent normal engine operation and trigger the warning light. Generally, engine warning lights have four patterns: steady yellow, flashing yellow, steady red, and flashing red. The severity increases from steady to flashing and from yellow to red, with flashing red being most critical. When the engine light appears, follow these steps: First check if the engine is running normally. If there's noticeable vibration, black smoke, or other abnormalities - especially with a red light - do not restart the engine. If the engine can operate, turn it off for 5-10 minutes. Without pressing the brake (or clutch for manual transmissions), activate the ignition to ON position to initiate system self-diagnosis. After 5-10 seconds, check if the warning light disappears. If the light persists, visit a service center immediately. Technicians can use diagnostic tools to retrieve trouble codes and perform targeted repairs.