What Causes the RPM Limiter Light to Illuminate?

[LeBrooke]

Here are the specific reasons why the engine RPM function restriction indicator light may illuminate: 1. Spark plug carbon buildup: Carbon deposits on spark plugs can cause poor engine performance, manifesting as difficult starting, unstable idle, poor acceleration, backfiring during sudden acceleration, excessive exhaust emissions, and increased fuel consumption. 2. Oxygen sensor malfunction: The oxygen sensor is a relatively durable component that can last 3 years or longer with proper fuel quality. If the warning light comes on, check if the oxygen sensor connector is loose. 3. Engine knocking: When the engine inhales the air-fuel mixture, if spontaneous combustion occurs before the compression stroke reaches the intended ignition point due to uncontrolled factors, the resulting powerful shockwave opposes the piston movement, causing engine vibration. This phenomenon is called knocking, which presents as reduced vehicle power, excessive engine noise, and in severe cases, accompanied by piston slap sounds.