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Bad Crankshaft Position Sensor: Symptoms, Causes, and Fixes

This article will focus on Crankshaft Position Senor symptoms. Arguably the most important sensor in your vehicle.

The vehicle onboard computer, also known as the Electronic Control Module (ECM), monitors and analyzes data from the sensors then translates its findings into codes. Compression in the cylinders, engine temperature, fuel consumption, and more, are all monitored with sensors. When the orange engine warning light on the dash lights up, it’s means there’s a problem. What’s going on and how do you repair the problem?

One of the reasons the check engine indicator light comes on could be a bad Crankshaft Position Sensor (CPS). Some of the symptoms are the vehicle overheats or stalls and you don’t get the power you used to. Another indicator of a bad Crankshaft Position Sensor is you vehicle will not restart until the engine is cold. These are just a few symptoms.

Getting started, remember to follow good safety precautions as well as use proper tools for the proper job.

One of the reasons the check engine indicator light comes on could be a bad Crankshaft Position Sensor (CPS)
The Crankshaft Position Senor symptoms can only be addressed when the vehicle is further analyzed

What is a Crankshaft Position Sensor and What Does a Crank Sensor Do?

The crankshaft position sensor is a device which has a coil wrapped around it that generates a low voltage signal. The device transmits data as an electronic signal to the ECM, about the position of the crankshaft as certain functions occur. This data analyzes when essential functions happen, such as injection of fuel into each cylinder, compression, and ignition that creates engine RPM. The sequence of the timing of all those functions as well as others determine how the engine performs.

The Crank Sensor will generate data that measures engine RPM as it passes the sensor. This information will be used to calculate if the correct firing order of the fuel injectors as well as other important functions like the order that the injectors fire, happens in the correct order as the engine was designed for them to do.

Where is the Crankshaft Position Sensor?

The crankshaft position sensor is located on the bottom of the engine between the engine and the transmission. Although the crank position sensor is located between the engine and the transmission the exact location depends on the manufacturer. On some engines it might require the removal of a tire in order to get to it. Keep in mind if you need to jack the vehicle up, make sure you have all the safety procedures in place first.

Symptoms of a Bad Crankshaft Position Sensor

1
Stalling

When the engine stalls it clearly indicates a problem. When you stop in traffic or begin a trip the vehicle starts then shuts down. Engine stalls can be a consequence of conditions such as clogged fuel injectors, a faulty fuel pump or incorrect data from a faulty crankshaft position sensor to the engine control module.

2
Poor performance

This is a general term with specific conditions. It could be that you notice it takes more to fuel cover the same distance as it did in the past. The climate control may not seem to operate as efficiently as it used to or sluggish acceleration

3
The tachometer does not register engine RPM immediately upon startup

Your vehicle is designed with specific tolerances that allow for peak performance. If the sensor does not indicate that the engine is rotating immediately, it’s possible the sensor is faulty.

4
Keep in mind the make, model and year of the vehicle

Crankshaft position sensor symptoms is not limited to one of the above scenarios. You could have a series of issues that happen as well. The vehicle might not start immediately, never stalls but hesitates when you accelerate

What Causes Crankshaft Sensor to Go Bad?

Some things that can cause the Crankcase sensor to fail include:

1
Sensor movement

Over time the vehicle is subject to different road conditions and issues. One issue that can cause crankshaft position sensor movement Is hitting the barrier in parking lots and road debris while driving. These conditions can cause the sensor to become loose.

2
Bad or faulty wiring

There is no absolute formula to indicate when your vehicle might begin to experience crankshaft position sensor problems. As vehicles get older it is more likely to happen.

3
Engine overheating

A simple routine function like not changing the oil and other engine coolants can cause the vehicle to run hot.

4
Moisture

As a car gets older, things can tend to lose the torque due to constant engine vibration. If the bolt that holds the crankshaft position sensor come loose moisten might seep in.

Bad Crankshaft Position Sensor Codes

The code that indicates a problem include:

  • P0335 -The engine ECM or electronic control module has notdetected the Crankshaft Position Sensor on engine start up.
  • P0339 – Possible problem could be exterior damage to the sensor. Solution look for exterior damage including wiring issues.
  • P0016 – Problems between the timing of the crankshaftand the camshaftsensor. Possible problem is most likely the code from the crankshaft position sensor does not match the code from the camshaft position sensor
  • P0017 – Problem between crankshaft and exhaust camshaft. The problem is most likely the two sensors are not in sync with each other.

There are additional codes that indicate other issues, however they will all involve the crankshaft position sensor. Diagnosis of crankshaft position sensor system problems take skill and understanding of automotive electrical and mechanical systems before you can tackle a task like this.

Crank Position Sensor Test

Use a diagnostic scan tool with a relearn function. Plug it into the vehicle’s onboard computer, start the vehicle then see if code P0335 comes up. This code will indicate there is a crankshaft position sensor problem. If you do get a code P0335, remove the sensor then check the voltage. One main indicator of crankshaft position sensor symptoms is the voltage is not about 12 volts.

This is an indication the sensor is bad and needs to be replaced. Driving on rough roads or damage from road debris can hit the engine and cause damage to the sensor in a new vehicle with very low mileage. If the crankshaft position sensor needs to be replaced, do it immediately. Remove and replace the old sensor.

To test the new sensor, after you replace it, reset the sensor,then clear the codes. After you have done this, start the car. If the repair was a success you will not see any engine warning light and the vehicle should start immediately. Also as mentioned above, check the voltage. The diagnostic device will not register any codes at all. Once the crankshaft position sensor has been replaced the vehicle should perform run better.

The crankshaft position sensor helps to ensures your vehicle runs according to the manufacturer’s specifications. The crankshaft position sensor must work correctly so the other essential functions perform as they were designed to do. The fuel injectors work out the firing time based on the position of the piston in the cylinder which is based on the crankshaft position sensor data analysis. If the engine cannot get a correct signal to the cylinders, problems begin to happen with engine performance. The new sensor will eliminate this problem.

The speed of the engine must also be accurate, so the electronic control module gets correct data that correlates with how fast the vehicle is traveling. When this is inaccurate the injectors could have errors in calculation based on inaccurate data, causing the engine to stall or shut down. That is why it is critical to test and replace the crankshaft position sensor if necessary.

A video about How to Test Crankshaft and Camshaft Position Sensors

How to Fix a Bad Crankshaft Sensor?

Remove and replace the bad crankshaft position sensor. This is a self-contained device that must be replaced if damaged. The crank position sensor will most likely be held in place with a 10 MM bolt. The proper tool is usually the 10 MM short socket. Before installing the new one slightly lubricate it and the O ring with engine oil and put it back in. After you have re installed the new crank position sensor start the car, if you do not get a code you are good to go. Reset the computer by selecting erase codes in the diagnostic scan tool then select yes. If the repair was a success you will not see any engine warning light and the vehicle should start immediately.

How to Start a Car with a Bad Crankshaft Sensor?

The vehicle might start after the engine cools down, however in some cases the car will not be able to be restarted. Overall it not a good idea to continue to start the engine with a faulty crankshaft positions sensor if will start at all. Manufacturers install sensors to alert you to a problem.

A vehicle can run for hundreds of thousands of miles if maintained properly. Anytime the check engine light come on, it is an indication of an issue which needs further analysis. The Crankshaft Position Senor symptoms can only be addressed when the vehicle is further analyzed. The crankshaft is the essential backbone of the engine. Without a crankshaft the power produced in the cylinders can’t be converted to forward motion.

Take care of the vehicle, by using recommended lubricants, follow maintenance schedules and if the vehicle hits something while on the road do a thorough inspection of the undercarriage as soon as possible.

How Serious is the Problem?

Anytime the check engine indicator comes on it’s a problem. The purpose of the light is to warn you of a problem. Check your owner’s manual to see if it has a section devoted to sensors in general and crankshaft position sensors specifically. This is a serious problem.

The only way to know what has caused the problem is to do a diagnostic test which will give you a code that corresponds to a specific problem. You can probably drive a vehicle with the ‘Engine Oil Change Due’ message on for a thousand miles, even that is pushing it, and might not cause a problem. Eventually you need to change the oil. On the other hand, you must change a bad crankshaft position sensor as soon as possible.

The orange check engine symbol is a start in the process to determine if you have a problem and how serious the problem might be. If it comes on, the vehicle most likely has a serious problem that needs to be addressed as soon as possible. In addition to crankshaft sensor symptoms there might be other issues such as emission control sensors.

Think of it as the manufacturers fail safe to let you know the issue should be addressed right way. The ECM displays a code that needs to be diagnosed immediately. As mentioned before, road conditions, missed maintenance and vehicle age, all factor into a possible crankshaft position sensor malfunction.

This problem can cause other issues such as engine timing issues. The crankshaft position sensor needs to be in proper working order, so your vehicle performs at its was designed to perform all the time. If ignored more problems could affect your vehicles performance, up to and including permanent damage.

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Tim MillerFounderOBD Advisor

I’m Tim Miller from Denver, Colorado. I’m the founder of obdadvisor.com, an automotive blog about "Diagnostic Tools and Auto Repair". My fan page is facebook.com/autozikcom. I've been working as an automotive mechanic and blogger for over 10 years writing articles to share my experiences and expertise.

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