What problems will occur if the knock sensor is broken?

[MacMason]

If the knock sensor is broken, it will cause engine shaking, generate noise, the fault light will turn on, and in severe cases, it may lead to serious damage to the firmware. Here is some extended information: 1. Knock is an abnormal combustion caused by irregular pressure in the combustion chamber. The combustion process in an engine is very complex, so it requires extremely precise design and control. Even a slight control error or irregularity can cause abnormal combustion, and "knock" is one such form of abnormal combustion. 2. To prevent knock, the knock sensor is an essential component, as it allows the electronic control system to adjust the ignition timing. During engine operation, factors such as excessive ignition timing advance, engine load, temperature, and fuel quality can cause engine knock. When knock occurs, the combustion of gases happens before the piston reaches top dead center. In mild cases, it produces noise and reduces engine power, while in severe cases, it can damage the engine's mechanical components.

[DiIsabel]

After repairing cars for over 20 years, I can tell you a faulty knock sensor is no trivial matter. It monitors abnormal vibrations inside the engine with ear-like sensitivity. When it fails, you'll notice obvious symptoms like sluggish acceleration and engine shaking, often accompanied by the check engine light. Since the ECU can't receive correct signals to adjust ignition timing promptly, prolonged driving may worsen knocking, causing piston ring wear or cylinder damage - my regular customers often spend over a thousand dollars fixing this. Fuel consumption will noticeably increase too, especially when running AC. If you hear strange clicking noises, get it professionally checked immediately. Don't let minor issues turn into major repairs.

[MacVivienne]

From a technical perspective, the knock sensor primarily monitors engine knocking phenomena to ensure smooth combustion. If it fails, the ECU will enter a protection mode by retarding ignition timing, resulting in reduced power output and sluggish acceleration. Prolonged uncontrolled knocking can increase cylinder pressure and temperature, accelerating wear on pistons and valves, and even damaging the crankshaft. In my experience designing engine systems, this may also cause excessive emissions, compromising environmental performance. It's advisable for vehicle owners to pay attention to dashboard warning lights and regularly scan for trouble codes using an OBD scanner. Replacing the sensor during repairs is relatively straightforward, but it's crucial to ensure the wiring harness connectors are in good condition.

[EllianaFitz]

When driving doesn't go smoothly, if the knock sensor is broken, the car accelerates sluggishly, consumes more fuel, and the engine light keeps staying on. I encountered this when I first started getting into cars—the engine buzzed like it was about to fall apart. The mechanic said the sensor failure caused the ECU to mess up the ignition timing. Simply put, it can't control the knocking, which can damage internal engine parts over time. Now, whenever I feel something's off with the car, I check the sensor's condition. Replacing a new one only costs a few dozen bucks. Anyway, don't keep driving with it broken—it affects safety and burns money.