What are the steps to test the crankshaft position sensor?

[TimothyRose]

Testing method for the crankshaft position sensor is as follows: Turn on the ignition switch and measure the voltage between the two signal wires and ground, which should be 1.4V. This is the preset voltage on the signal wires by the engine control unit. When starting the engine, the signal voltage of the crankshaft position sensor should be close to 1.6V. If there is an open or short circuit inside the sensor, signal wiring, or engine control unit, the computer will be unable to receive the crankshaft position signal, and the engine will fail to start. Additional Information: If the crankshaft position sensor is damaged, the rotation angle of the crankshaft cannot be determined, and the engine computer will not receive the signal from the crankshaft position sensor. To protect the engine, it will not ignite or inject fuel. The symptoms exhibited by the car will include no high-voltage electricity, no fuel injection, and failure to start. The most obvious sign is the illumination of the engine fault light on the dashboard.

[DiKate]

As someone who frequently deals with engine issues, I believe checking the crankshaft position sensor requires a systematic approach. First, I turn off the engine and disconnect the negative battery terminal to prevent short circuits. Then, I visually inspect the sensor for oil stains, cracks, or damaged connectors, ensuring the wiring connections are secure. Next, I connect an OBD-II scanner to the vehicle's port to read fault codes. If codes like P0335 related to the sensor appear, it's a clue. I then set a multimeter to the resistance mode and measure the resistance across the sensor terminals to verify if it matches the manufacturer's specifications (typically ranging from a few hundred to a thousand ohms). Any deviation indicates a problem. After that, I start the car but only let the engine idle, using the multimeter in voltage mode to monitor the output signal voltage for stability. Normally, it should fluctuate between 0.5V and 5V. If the readings are unstable, I use an oscilloscope to check if the waveform is regular—irregular waveforms suggest a fault. The entire process requires attention to detail because the sensor controls ignition timing. If it fails, the car may shake or fail to start. Therefore, after testing, I clean any surrounding oil stains to avoid affecting future readings. Regular inspections like this can prevent costly major repairs.

[Rose]

I personally love DIY car repairs, and checking the crankshaft position sensor is simple and cost-effective. First, I disconnect the battery for safety; then unplug the sensor connector to check for corrosion or looseness. I use my multimeter to measure the resistance value to see if it's within the normal range. Next, I power on the car and monitor the voltage output changes with the meter. If the signal is weak or unstable, the sensor is likely faulty. Common causes include dust buildup or water exposure—try cleaning it and testing again. Although professional equipment is better, DIY tools are sufficient, saving a trip to the shop. Also, don’t forget that a faulty sensor can cause hard starts or high fuel consumption, so catching it early can avoid a tow truck.

[MacGabriela]

I don't know much about cars, but when problems arise, I do simple sensor checks. If the car won't start or stalls, I visually inspect around the sensors for oil stains or damage; then I open the trunk to check the OBD port, buy an inexpensive scanner to plug in and read the codes; if the codes indicate an issue, I ask my neighbor to help measure the resistance with a multimeter. Keeping it simple works fine—no need for complex tools, saving hassle and avoiding unnecessary tinkering. Anyway, if a sensor fails, the car's warning light will come on, and after checking, just replace the faulty part promptly.