All modernized vehicles are equipped with a crankshaft position sensor. This vital component has the task of monitoring the crankshaft’s rotational position as well as speed. The crankshaft position sensor also has the job of sending data to the engine control unit, so that the correct adjustments can be made should there be any issues, or malfunctioning parts. For a failing crankshaft position sensor, there are several symptoms that you should focus on. Lots of engine models will stop working if the crankshaft sensor fails to send precise signals.
Can A Bad Crankshaft Sensor Cause No Start?
A bad crankshaft position sensor is indeed a common cause of no starts. The signal from the crankshaft sensor goes to the ignition module or the PCM, that switches the ignition coil (or coils) both off and on.
So, if you have a bad or a faulty RPM signal, a faulty ignition module my not be successfully switching the coil (or the coils) off and one.
What Are Some Common Crankshaft Position Sensor Symptoms?
Check out some of the most common crankshaft position sensor symptoms that you should look out for.
The ‘Check Engine Light’ Illuminates
Just about all of us have seen the dreaded “check engine light” illuminate from our dashboards. The light can come on for a variety of reasons- including a faulty crankshaft position sensor. Many times, it will stop working because of becoming overheated. This will cause the “check engine light” to turn on. If this is the case, it will be to your benefits to allow the engine to cool down a bit. Then, take your car to a mechanic so that he or she can properly diagnose the issue.
Reduced Gas Mileage
Without precise timing information, fuel injection will not occur as effectively and efficiently as it should. This will lead to your engine needing to use more fuel.
Botched or Erratic Starting
Botched or erratic car starting issues is another serious crankshaft position sensor symptom. The computer will receive a malfunction code, once the sensor is completely kaput. This symptom will usually begin with difficulty in starting your car. This symptom will eventually lead to a dead car and one you have to get fixed ASAP. A circuit problem or an electrical connection can be attributed to your car failing to start or starting with several issues.
A cylinder misfiring is yet another response to some sort of problem with your crankshaft position sensor. A failing crankshaft sensor is not able to provide the correct information regarding the piston position. This results in one of the cylinders to misfire. Problems with the spark plug will also trigger a similar response. But if the issue persists after handling all the other problems, then you can place a bet on the crankshaft sensor being the cause.
Backfiring and Stalling
Backfiring and stalling are yet two more issues that indicate a problem with the crankshaft sensor.
With both of these issues, your vehicle will run but the engine will turn off unexpectedly. Misfiring will also be an unwelcomed and unexpected event too. If you decide to ignore the stalling and misfiring your car is doing, then you risk your car engine shutting off permanently.
Stagnant and Slow Response from Accelerator
For a faulty crankshaft sensor, the right data will not be sent regarding the position of the cylinders. There will be an ill-timed gap between the computer receiving data and the application of the data. Because of this, the car accelerator will hesitate and not offer a real-time response.
How Do I Test A Crankshaft Sensor?
Trouble Codes the ‘Check Engine Light’
If you are experiencing that “check engine light” being on, then your ECU or your engine control unit has documented some kind of trouble code/alert. Check the diagnostic codes with your diagnostic scan tool. The trouble codes that are between P0335 and P0338 are in direct correspondence to the to crankshaft sensor. This test is probably one of the most accurate to perform. But the unfortunate side to this test, is that there is a great chance that your crankshaft sensor is very worn by the time the “check engine light” illuminates from your dashboard.
So, is there a more proactive test you can perform on your crankshaft sensor? Yes!
Crank Sensor Test
The next test you can perform requires that you get your diagnostic scan tool. One of the settings of your tool gives you a reading of your vehicle’s engine speed in RPMs or in revolutions per minute. Since the scanner gets its data from the crankshaft position sensor, you want to make sure that the scanner can read the engine RPM as the engine cranks. Your scan tool should have an output between 100 and 500 revolutions per minute or RPMs. If you don’t have this reading, then you have a faulty crankshaft sensor. For a reading of zero, you have a crankshaft sensor that has completely failed.
Using a Multimeter
We get that not everyone has a scan tool handy. So, another way you can test your crankshaft sensor is to use a multimeter, which are far more common than the scan tool. They are quite handy in diagnosing a multitude of electronic parts- and they can also measure current, resistance and voltage. Remove the crankshaft sensor and then test for resistance. Place one end of the multimeter to each of the wiring leads of the sensor. If you have a reading of zero resistance, then you have a short circuit. If you have a reading of infinite resistance then you have an open circuit. But regardless of if you have a reading of zero of infinite resistance, then “all roads lead” to a faulty crankshaft sensor. If you have any other reading, check that reading against the manufacturer's recommendations and specifications. You can also check your crankshaft sensor with your multimeter – and use it to evaluate the output voltage while the engine cranks. You will need help to do this test.
Carefully probe the wiring connectors and calculate the output voltage in AC millivolts. While a common reading is about 200 millivolts, this will vary, depending on your car. For a reading that has no output voltage, then you know that your crankshaft sensor is bad.
With these tests, you can find the source of your problem. These tests will also confirm that you either have to visit your mechanic, or spend your time zeroing in on the issue at hand, instead of guessing.
Why Crankshaft Position Sensors Fail In the First Place?
There could be a number of reasons that a crankshaft sensor fails. We have some of the reasons below!
The magnet, is a vital component for the crankshaft sensor, but it is prone to issues. The magnet can attract the smallest of metal debris or shavings created by engine friction. If those metal debris and shavings stick to the sensor or the wheel, they will thwart the sensor's measurements. The metal debris can also begin a bridge to the wheel and the sensor. Since your crankshaft sensor is designed to calculate the movements of the wheel at a certain distance the closeness will throw those measurements off.
Wiring and Circuitry Issues
The internal wires and circuitry that connect the crankshaft sensor to your car’s engine and power could be burnt out. Just one small short circuit is enough to cause huge problems with the crankshaft sensor.
Burnt out sensors may cause the sensor miss receiving power. Furthermore, the sensor may not be transmitting a signal to the ECU.
How Much Does It Cost to Replace A Bad Crankshaft Sensor?
Typically speaking the repair/replacement of a crankshaft position sensor can cost between $200 and $260. Labor is about $250 while parts are between $90 and $130. Prices depend on where you go for the repair.
How Long Does It Take To Replace A Crankshaft Sensor?
With the labor involved in replacing a crankshaft sensor, you can count on between an hour and a half, and two hours.
Is It Hard To Replace A Crankshaft Sensor?
A mechanic who has to perform a crankshaft sensor repair will spend a considerable amount of time removing the crank sensor, so as not to damage anything else. They can be a bit difficult to take off, due to sensor’s ability to get stuck in the block. The sensors also have a long stem, making removal difficult. After the sensor has been taken loose, the mechanic will grasp it and begin the work of the repair.
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