Symptoms of a Faulty Crankshaft Position Sensor?
2 Answers
The symptoms of a faulty crankshaft position sensor are: 1. The engine does not ignite or inject fuel; 2. If the crankshaft position sensor fails while driving, the engine will stall. The function of the crankshaft position sensor is to determine the position of the crankshaft, that is, the rotation angle of the crankshaft. It usually works in conjunction with the camshaft position sensor to determine the basic ignition timing. The engine ignites at the end of the compression stroke. The crankshaft position sensor calculates signals to determine whether the piston in the cylinder is in the compression stroke. Combined with the signal from the camshaft position sensor, it can determine which cylinder to ignite. The specific ignition timing also depends on the current vehicle load and whether the cylinder is knocking. If the crankshaft sensor is faulty, the engine ECU cannot receive the crankshaft position signal and cannot determine which cylinder to ignite. To protect the engine, the ECU will stop ignition and fuel injection, meaning the vehicle will not start or stall while driving.
Symptoms of a faulty crankshaft position sensor are common in my repair experience. The engine often refuses to start—turning the key all the way yields no response, especially noticeable during cold starts. Another frequent issue is sudden engine stalling while driving, particularly during acceleration or turns, which can be downright terrifying. The tachometer on the dashboard behaves abnormally, with the needle either stuck or erratic, while the yellow check engine light inevitably illuminates as a warning. The root cause is typically the sensor's failure to monitor crankshaft position, preventing the ECU from precisely controlling ignition timing and fuel injection. This also leads to worsened fuel economy, with unexplained increases in consumption. Long-term neglect may trigger chain reactions, damaging components like spark plugs or engine parts. It's advisable to promptly check for loose or contaminated wiring and replace the sensor if necessary—don’t gamble with safety.
