How to test a two-wire crankshaft position sensor?
2 Answers
Here is the relevant introduction about the crankshaft position: 1. The function of the crankshaft position sensor is to determine the position of the crankshaft, that is, the rotation angle of the crankshaft. 2. It usually works in conjunction with the camshaft position sensor to determine the basic ignition timing. 3. Essentially, it calculates through the signals from the crankshaft position sensor and the camshaft position sensor. The crankshaft position sensor can indicate which cylinder's piston is at the top dead center, while the camshaft position sensor can determine which cylinder's piston is in the compression stroke. 4. In this way, the engine control unit knows when to ignite which cylinder.
I often help friends with car repairs, and testing a two-wire crankshaft position sensor isn't that complicated. First, you'll need a multimeter—this tool is super useful for measuring voltage and resistance. Pop the hood, locate that small sensor, usually near the crankshaft area. Disconnect the engine's power supply to avoid short circuits and protect yourself. Set the multimeter to DC voltage mode, and check the reading changes when cranking the engine—no signal means there's an issue. Inspect the wiring connections for looseness or corrosion. These two wires consist of one power supply line and one signal output line; the signal voltage should fluctuate between 0.5V and 4.5V to be normal. If the voltage stays steady or reads zero, the sensor is likely faulty. I also prefer using an oscilloscope to check if the waveform is smooth, as irregular fluctuations can reveal internal faults. Don’t forget to scan for error codes from the ECU side. If you want to save money, replacing the sensor yourself costs just a few bucks—way cheaper than a repair shop. If your car has starting issues or rough idling, try this method first. It's simple, beginner-friendly, and doesn’t take much time.
