What is an engine without a crankshaft or the crankshaft position sensor? This component is crucial to the engine’s ability to generate power to move a vehicle from one place to another.
The crankshaft position sensor is an essential engine management sensor. It works together with the other components like the Powertrain Control Module (PCM) within a car’s engine compartment to generate power for the engine.
A slight defect on the crankshaft sensor can be a big challenge for a vehicle’s engine because it may not start. Besides that, several symptoms of a bad crankshaft position sensor are discussed in the subsequent sections below.
What is a Crankshaft Position Sensor?
The crankshaft position sensor is an electronic component used in IC engines to track the speed or position of the crankshaft.
The powertrain control module (PCM) highly depends on the crankshaft data to manage ignition system timing, fuel injection, and other engine-related variables.
Both petrol engines and diesel engines rely on crank sensor performance for optimal performance.
Before the invention of the electronic crank sensor, petrol engine distributors needed manual adjustments based on a timing mark.
The crankshaft position sensor works along with a camshaft position sensor to observe the interaction between valves and pistons within the engine. This proper interaction between the valves and pistons is a crucial aspect in engines featuring variable valve timing.
This technique is also employed to synchronize a four-stroke engine during startup, informing the management system about the appropriate moment for fuel injection.
Additionally, the CKP sensor is frequently utilized as the primary means of determining engine speed in revolutions per minute (RPM).
What Does a Crankshaft Position Sensor Do?
The crankshaft is a rotating assembly inside the engine that connects to the pistons and connecting rods. When the engine is running, the linear motion of the pistons causes the crankshaft to turn, thereby creating the rotational force needed to move the vehicle.
As you might guess, the CKP sensor measures the position and speed of the engine’s crankshaft. The sensor creates a signal by reading a toothed or notched wheel that is usually located on the crankshaft or harmonic balancer.
For this reason, the crankshaft position sensor’s location is often at the front bottom side of the engine, though, its location can vary from vehicle to vehicle.
The engine computer, which is often referred to as the powertrain control module (PCM), uses the CKP sensor signal when calculating spark timing and (in most cases) fuel injector synchronization.
The PCM may also use the CKP signal when managing other functions, such as the variable valve timing system if the vehicle is so equipped. On all vehicles built after 1996, the module also uses the CKP sensor to detect an engine misfire.
Crankshaft Position Sensor Location
Your vehicle’s crankshaft position sensor is located near the bottom of the engine by the crankshaft. That makes sense because it’s the crankshaft position sensor’s job to measure the crankshaft location.
When you’re trying to track down the crankshaft position sensor, look towards the engine’s bottom, generally on one of the sides.
Since the sensor is so far down in the engine, it can be hard to locate and even harder to remove and replace if you have a faulty one.
Symptoms of a Bad Crankshaft Position Sensor
The symptoms of a bad or failing crankshaft position sensor might initially seem intermittent. Sometimes, they can be confused with another engine fault. However, the symptoms become more obvious as the crankshaft position sensor continues to fail.
However, a bad or failing crankshaft position sensor will manifest the following:
#1. Check Engine Light.
As I said before, the most common symptom of a bad crankshaft position sensor is a check engine light. The good news is that if you have a check engine light, then your ECM has reverted to default measurements.
While this might cause a few performance issues, it should help prevent further damage from occurring. However, the longer you leave the problem unaddressed, the worse it will become.
#2. Excessive Engine Vibrations.
If your engine has a faulty crankshaft position sensor, then it isn’t optimizing any performance. Even worse, it might be utilizing incorrect readings to determine fuel and ignition timing. If the ECM doesn’t time things correctly, you’re in for a bumpy ride.
Even worse, the problem is only going to get worse until you fix it, and it’s only a matter of time until further damage occurs.
#3. Reduced Engine Performance.
Whether you have a check engine light or not, a faulty crankshaft position sensor will lead to reduced engine performance. Whether it’s default values or the wrong values entirely, anything less than optimal timing is going to reduce your overall performance.
Top speed and acceleration are the two most significant areas in which you are going to see a reduced performance.
Keep in mind that an engine that isn’t performing correctly is also going to have a reduction in fuel economy, but unless you’re paying close attention to how many miles you get out of each tank, you might not notice.
#4. Difficulty Starting Your Vehicle.
If your defective crankshaft position sensor is extremely out of sync, you might have trouble getting your vehicle started. Furthermore, you might have difficulty keeping it started.
This is usually only a problem when the problem has persisted for some time, and you likely have multiple other underlying issues too. Moreover, it’s not usually a problem if you have a check engine light and the ECM has defaulted to predetermined values.
Instead, it’s a problem when the crankshaft position sensor is feeding inaccurate readings and your ECM doesn’t realize it.
#5. Engine Stalling.
While this indicates a severe fault, it’s possible that a faulty crankshaft position sensor could lead your vehicle to stall. This happens when the ECM is sending all the wrong fuel and ignition timing to each cylinder.
Typically, it will take a while for a problem to get this bad, and if it is, there’s a good chance there’s further damage that you’ll uncover after you replace the crankshaft position sensor.
#6. Engine Misfires.
While it’s unlikely that a vehicle with a check engine light on will misfire, if the ECM uses incorrect positions of the crankshaft, it becomes incredibly likely. Even worse, if you have an engine that’s misfiring, it’s only a matter of time before engine damage occurs.
The longer you let a misfire happen, the worse it’ll get, and the more expensive the eventual repairs will be. If you have a misfire, get repairs as soon as possible.
Causes of a Bad Crankshaft Position Sensor
- Age and wear: With time, the crankshaft position sensor may degrade or wear out because of constant exposure to extreme pressure, vibration, heat, and other harsh operating environments. These harsh operating conditions may lead to the failure of the sensor.
- Physical Damage: Accidental damage to the sensor or its casing during car repairs or maintenance may also lead to its failure.
- Moisture or Corrosion: The internal parts of the sensor may damage due to corrosion or moisture.
- Damage from heat: Extreme heat for a long time may damage the internal parts of the camshaft position sensor. A high temperature may force the internal parts to expand, while a low temperature may cause brittleness or cracking.
- Contaminants: The contaminants such as debris or oil may gather inside the sensor, which affects its capability to accurately measure the crankshaft position. This may lead to erratic readings and poor performance.
- Manufacturing Material: The manufacturing material of the sensor plays a vital role in its efficient performance. A sensor made of poor material can’t work efficiently for a long time.
How to Diagnose a Faulty Crankshaft Position Sensor?
Diagnosing a faulty crankshaft position sensor is relatively straightforward, especially if you’re familiar with automotive troubleshooting. Here are a few methods you can use to identify whether the sensor is at fault:
#1. Scan the Trouble Codes.
The first step in diagnosing a faulty crankshaft position sensor is to check for any trouble codes using an OBD-II scanner. This scanner can read the error codes stored in your vehicle’s ECU and will likely point to a sensor issue.
#2. Inspect the Wiring and Connections.
Check the sensor’s wiring for any signs of damage or wear. Damaged or frayed wires can cause the sensor to malfunction. Ensure the connections are secure, and the sensor is properly aligned with the crankshaft.
#3. Use a Multimeter to Test the Sensor.
If you have access to a multimeter, you can measure the resistance of the sensor. A functioning sensor should show resistance within a specified range. If the reading is outside this range, the sensor is likely faulty and needs to be replaced.
How to Replace Your Crankshaft Position Sensor?
You can replace your own crankshaft position sensor to save yourself $100 or more on the labor cost of having a mechanic do it. This sort of thing requires a modest amount of mechanical skill and a somewhat extensive automotive tool kit.
Once you’ve found it, you can replace your failing crankshaft position sensor using the following steps.
- Step 1: Disconnect the negative terminal of the car’s battery.
- Step 2: Access the crankshaft position sensor and carefully remove any non-essential components that might be in the way, such as the timing cover. If your car’s crankshaft position sensor is mounted at the front of the engine, you might also need to remove the serpentine belt along with the crankshaft pulley. If the bad crankshaft position sensor is mounted near the transmission, you might have to remove the starter motor.
- Step 3: Note the three wires coming out of the crankshaft position sensor. Take a picture with your phone or label them in a side drawing. They are the input, output, and the ground wire. Carefully set them aside without letting them touch anything wet or metallic.
- Step 4: Remove the two small bolts holding the sensor in place.
- Step 5: Compare the bad crankshaft position sensor to the new one to ensure they match.
- Step 6: Reconnect the three wires to the sensor in the same ports that you removed from the bad crankshaft position sensor. If they are not in the correct ports, the sensor will fail to work, and you’ll return to square one!
- Step 7: Reconnect the mounting bolts holding the new crankshaft position sensor in place. Then, reinstall all the other components you removed in reverse order. Finishing with reconnecting the car’s battery.
- Step 8: Clear all the codes and start the car. Check to see how it idles. Rev the engine a little to see if the symptoms of a bad crankshaft sensor return.
If the car seems to operate normally, you can take it out for a 15 to 20-minute test drive. Ideally, you want to tool around town roads and residential streets to make sure there aren’t any stalling, misfiring, or surging acceleration issues.
Then, you can take it out to the highway to see how it handles accelerating, like merging and passing at high speed.
How do you Test a Crankshaft Position Sensor?
A crankshaft position sensor can be tested with the help of a scan tool (e.g., OBDII Scanner). However, not everyone can access a scan in some cases, except a rented one.
There is another common way to test a crankshaft sensor, and that is with a multimeter. To test a car’s crankshaft position sensor:
- Locate the sensor’s plug and remove the crank sensor.
- Attach each of the multimeter’s ends to the sensor’s wiring lead.
- Once this is done, check the reading on the multimeter.
If the multimeter reads zero (0) or displays an infinite resistance, it means the crankshaft sensor is bad. But if it shows anything other than zero or infinite resistance, endeavor to check it against the ideal reading from the vehicle’s manufacturer’s manual.
Finally, if the reading is not close to what the manual recommends, you may need to replace the crankshaft position sensor.
How much does it cost to replace a crankshaft sensor?
Replacing a crankshaft sensor does not cost a fortune. The estimated price for a crankshaft sensor replacement is around $194 to $258. Labor costs may vary between $104 and $133, while the parts could be valued at $90 to $125.
However, the cost of replacing a crankshaft sensor may differ from one location or service provider to another. So, it would be best to check out an automobile parts seller and a service provider near you.
FAQs.
Q: Can a vehicle work without a crankshaft sensor?
A car cannot run without a crankshaft sensor because it is an essential component among other sensors that interact with the engine. The sensor is so sensitive in the engine running process, from the ignition spark.
So, if you have a defective crankshaft position sensor, your car’s ignition spark will be hindered; and the effect will be a difficulty in starting the vehicle’s engine.
If you face this kind of challenge, it would be best to consult an expert auto mechanic to rectify the issue as soon as possible.
Q: Can I reset my crankshaft sensor?
Yes, you can reset your vehicle’s crankshaft position sensor. If a vehicle’s engine stalls consistently and eventually goes off without starting for a long time, it is most likely that the issue is traceable to a faulty crankshaft position sensor. The crank sensor may require a reset.
To completely reset a vehicle’s crankshaft sensor, simply do the following: turn off all accessories in the vehicle, then start the vehicle’s engine and allow it idle for about 2 minutes while on “Park” or “Neutral.” After that, accelerate the car at 55 mph.
Then cruise at the same 55 mph for about 8 – 10 minutes to get the vehicle engine at operating temperature. Again, cruise for some more 5 – 6 minutes. Then, decelerate down to 45 mph without applying the brakes.
Now, perform at least 4 decelerations of 25 seconds each and return to 45 mph for about 15 seconds between each deceleration.
Finally, accelerate back to 55 mph for 2 minutes and stop the vehicle. After that, idle for about 2 minutes while the brake is applied, and the clutch is depressed.
Q: How do you jump a crankshaft sensor?
Jumping a crankshaft position sensor in a car depends on the state of the crankshaft position sensor’s fault. In any case, if you can access a mechanic, it would be better to do so; if not, you can find out how to start a car with a bad crankshaft position sensor.
To perform a temporary fix for a crankshaft position sensor, simply locate the vehicle’s crankshaft position sensor plug and remove it. After that, apply a starting fluid.
Then, start the car again. You’ll be lucky to have the car’s engine start after this process because, in most cases, a defective crank sensor usually requires a complete replacement.
Q: How often should you change crankshaft sensor?
A vehicle’s crankshaft position sensor does not easily go bad, but it is subject to wear and tear; hence, it would require a replacement at that time.
The primary reason that will require a prompt replacement of a vehicle’s crankshaft is when the car starts manifesting the symptoms of a bad crankshaft sensor.
Besides that, if you discover that your car’s fuel consumption economy is getting poorer by the day, it calls for a diagnosis of the crankshaft sensor in case you would need to replace it.
Q: Can I bypass a crankshaft sensor?
No, you can’t bypass a crankshaft sensor to enable it to work again after it goes bad. If you manage to devise some manipulations on it, it may crank and not power the vehicle’s engine to start.
The best thing to do when a car’s crankshaft position sensor becomes faulty is to replace it as soon as possible. It doesn’t cost a fortune to replace so that the engine is not completely damaged.
Q: What happens if you drive without a crankshaft position sensor?
If you drive without a crankshaft position sensor or a faulty one, the vehicle will consistently stall on the road at all speeds and eventually stop. Apart from that, you will experience excessive vibrations from the engine.
Also, the most severe occurrence would be when the vehicle stops, as it may be challenging to start the engine again.
Therefore, once you notice that your car’s crankshaft sensor may be faulty, it would be best to consult an expert auto mechanic to check it out quickly.
Final Words
A crankshaft position sensor is as important as other Sensors that make your vehicle work effectively. The part plays a vital role in generating power for the engine.
So, you shouldn’t try to manage the symptoms of a bad crankshaft positions sensor. Another thing you shouldn’t also try to manage is the symptoms of a bad camshaft sensor.
If you notice any of these symptoms discussed above in this article, endeavor to seek the service of a professional auto mechanic. In any case, the worst burden would be to replace the crankshaft sensor, which does not cost a fortune.