The most common symptoms of a faulty knock sensor are engine noises, flashing dashboard or “Check engine” lights and diminished fuel economy. These symptoms are most common when the vehicle is travelling at highway speeds or carrying a heavy load. To properly assess the condition of the knock sensor, compare engine performance to its factory specifications found in the vehicle’s manual.
Flashing or activated warning lights are the most common indication of a bad knock sensor. A faulty knock sensor pairs activated or flashing warning lights with strange engine noises, which are the most common symptoms associated with faulty knock sensors.
Common engine noises associated with faulty knock sensors include sputtering, knocking and pounding sounds. These noises stem from pre-ignition, which results from fuel and air igniting inside the cylinders instead of burning evenly throughout the engine.
Faulty knock sensors also decrease fuel economy. Fuel efficiency decreases with faulty knock sensors because of an improper mixture of fuel and air. The engine cannot combust properly, which leads to higher emissions and reduced fuel economy.
A faulty knock sensor miscalculates the fuel to air ratio. When this ratio is not properly determined, the vehicle cannot accelerate nor use fuel efficiently. Faulty knock sensors disrupt communication between the engine and the vehicle’s computer. This disruption diminishes vehicle performance through a misallocation of fuel delivered to the engine.Learn More
According to Repairpal.com, symptoms of a bad knock sensor include poor acceleration, knocking noises during acceleration, poor fuel mileage and a visible check engine light. The symptoms of a bad knock sensor typically occur during heavy loads or at high speeds. Autopartswarehouse.com explains that the knock sensor has a direct effect on the engine’s ignition timing. A bad knock sensor causes a decrease in acceleration and fuel mileage.Full Answer >
A DPFE sensor is short for "delta pressure feedback of EGR" and monitors changes in the EGR system's pressure. The EGR, short for "exhaust gas recirculation," functions to suck back gases that have been exhausted by the engine to reburn them. This process reduces pollutants emitted by cars.Full Answer >
A vehicle's speed sensor is a monitoring device that measures the output of a transmission or transaxle in terms of wheel speed. This information is used by the engine control module to adjust the automobile's performance automatically in order to achieve optimum levels.Full Answer >
A knock sensor senses vibrations that occur during engine knock and allows the car's power train control module to reduce ignition timing to prevent knocking. The sensor is located on the engine block, cylinder head or intake manifold and is a piezoelectric material that creates a small charge when vibrated. Engine knock leads to engine damage and is caused primarily by poor fuel, deposits in engine or incorrect spark plugs.Full Answer >