What are the symptoms of a faulty camshaft position sensor?
2 Answers
During the starting process, symptoms such as crankshaft reversal and backfire in the intake manifold may occur. The car may experience unstable idling, severe shaking, lack of power during acceleration, increased fuel consumption, excessive exhaust emissions, and unpleasant black smoke from the exhaust pipe. These symptoms may indicate a damaged camshaft position sensor, and prompt inspection and repair are recommended. The functions of the camshaft position sensor are: 1. To collect the camshaft movement angle signal and input it into the electronic control unit (ECU) to determine the ignition timing and fuel injection timing. 2. The camshaft position sensor is also known as the cylinder identification sensor. To distinguish it from the crankshaft position sensor (CPS), the camshaft position sensor is generally denoted as CIS. 3. The function of the camshaft position sensor is to collect the position signal of the valve camshaft and input it into the ECU, so that the ECU can identify the top dead center of cylinder compression, thereby enabling sequential fuel injection control, ignition timing control, and knock control.
From a technical perspective, a faulty camshaft position sensor will exhibit a series of noticeable symptoms. For instance, the engine may become difficult to start or fail to start entirely, as it relies on this sensor to provide signals to the control unit for determining ignition timing. Once it fails, the engine will shake violently during startup, with unstable RPM fluctuations, and you'll feel a lack of power during acceleration—the car will struggle to move. The check engine light will definitely illuminate as a warning; it's not just for show. Worse yet, the engine may suddenly stall while driving, increasing the risk of accidents. Fuel consumption will also rise due to disrupted combustion efficiency. To diagnose the issue, use an OBD scanner to read the trouble code P0340 for confirmation. Replacing the sensor will restore normal operation. I recommend regularly inspecting the sensor wiring for corrosion to extend its lifespan and prevent unexpected failures. Don't overlook these small components—they are critical for safety when it matters most.
