What Happens When the Knock Sensor Fails?
2 Answers
Symptoms of a faulty knock sensor include noticeable vehicle vibration or abnormal engine noises, increased fuel consumption, and illumination of the engine warning light on the dashboard. Below are specific reasons for the engine warning light activation: 1. Irregular Maintenance: Approximately 50% of engine-related failures are caused by poor maintenance. 2. Incomplete Combustion: Poor engine combustion is a primary cause of the warning light. In automotive design, oxygen sensors are installed to monitor combustion status. If combustion is inefficient—such as high levels of hydrocarbons, carbon monoxide, or nitrogen oxides—it not only pollutes the environment but also leads to fuel waste and excessive engine wear. 3. Engine Knock: A dedicated knock sensor monitors engine knocking, which can cause severe mechanical damage or significant power loss. Knocking is categorized as detectable or undetectable. For undetectable knock, the engine control unit adjusts parameters to mitigate adverse effects. However, if the knock exceeds adjustable limits, the engine warning light will activate as an alert.
I remember when the knock sensor in my old car failed last time, the engine power noticeably deteriorated, especially when climbing hills or accelerating hard. The car struggled as if it was laboring, and the sound became particularly dull and rough. Fuel consumption also shot up, with a full tank covering dozens of kilometers less, which really hurt my wallet. Prolonged driving in this condition can lead to severe carbon buildup in the engine and even cause component wear, resulting in costly repairs. I recommend getting it checked at a professional repair shop as soon as you notice any abnormalities, such as the dashboard warning light coming on or the engine making unusual knocking sounds. Don’t wait until the problem worsens like I did, ending up replacing the entire sensor set and spending more money. During regular maintenance, ask the technician to take a quick look—it can save you a lot of trouble.
