What happens if the crankshaft position is not relearned

What happens if you don’t relearn the crankshaft position sensor? Your car won’t start. Or, because the ECU (electronic control unit) has been negatively affected, your normal driving experience will completely change.

In fact, the engine in your vehicle will have a terrible disorder including the following:

  • Problems with the car accelerating properly
  • The engine usually goes haywire since bad signals will be sent from the ECU
  • Over revving of the engine
  • Possible permanent damage to the engine

All of these problems are caused by not relearning the crankshaft position sensor. Therefore, it is important that you learn as much as you can about the crankshaft position sensor. To start, you need to know exactly what a crankshaft position sensor is.

What is a crankshaft relearning

In general, the definition of crankshaft relearning is to re-program, re-calibrate or re-engineer an engine. These actions are taken preemptively to ensure the engine functions properly after an engine has been tampered with.

Or, a crankshaft relearning will need to be performed after the engine of the vehicle has been replaced.

This is a process that needs to be performed right away, especially since the engine of any vehicle is just like the functionality of the human heart.

For instance, without the engine in a vehicle, the vehicle itself is as good as dead. Therefore, whenever the engine has been replaced or tampered with, this reprogramming has to be done in order to ensure that the engine will function properly.

Disadvantages of not relearning the crankshaft position sensor

Because of the role that the crankshaft position sensor plays in the functioning of any modern vehicle today, there is a wide range of disadvantages to not relearning the crankshaft position sensor.

Here are some of the most common disadvantages that you may experience with your vehicle if you don’t do this reset.

Engine Will Overheat

The crankshaft position sensor is responsible for managing the temperature of the engine and other components within the engine.

For instance, the sensors monitor the rotational speed of the crankshaft and its position by sending the info to the ECU. The ECU then uses this info to make the necessary adjustments.

Therefore, whenever the crankshaft position sensor is not working properly, the engine will overheat from the excessive build-up.

These problems can also cause damage to the crankshaft sensor, particularly if it leads to the plastic covering on the engine melting.

Problems with the Circuitry

Another problem that can arise from not relearning the crankshaft position sensor is issues with the circuitry. If the crankshaft position sensor is not working properly, these problems can lead to a faulty voltage that disrupts the signals sent to the ECU.

Intermittent Stalling

If you do not re-engineer or re-calibrate the engine after it has been replaced, your vehicle may begin to stall intermittently. Unfortunately, these issues can lead to very dangerous problems, such as losing power while driving on city streets and highways.

Acceleration is Uneven

Your driving will be affected by uneven acceleration problems. Since bad signals are being sent to the ECU, the ECU will not be able to adjust fuel injection or spark timing correctly.

Therefore, you will not be able to maintain a constant speed while accelerating. Instead, your car will accelerate slowly or unevenly.

Benefits of Relearning the Crankshaft Position Sensor

When you relearn a crankshaft position sensor, here are 2 benefits that you can receive.

It Keeps You from Experiencing Problems with Your Ignition

By re-engineering the engine after it has been tampered with, your ECU signals will ensure the vehicle ignites correctly. The driver will not be alarmed by unexpected ignition timing problems. In essence, this fresh start will ensure that you can crank your engine without any problems.

Uninterrupted Pleasant Driving Experience

Fixing or replacing an engine in your vehicle can be a very expensive and time-consuming process. This is especially true if you are not familiar with the engine and its components like the crankshaft position sensor.

However, if you know how to reprogram/relearn the crankshaft position correctly, you can hit the road again with an uninterrupted driving experience.

Simply put, you do not have to worry about vehicles that will not start or other issues that can cause your vehicle to not be operational.

How to relearn a crankshaft sensor?

The process for relearning a crankshaft usually differs from one car model to the next. As a general rule, the procedures are not difficult at all. However, if you choose to do so, you check with a professional auto repair service to do the re-engineering work for you.

Here is an example of the steps that you need to follow.

  • STEP 1: Connect the sensor scanner to the ignition of your vehicle. Without starting the car, turn on the car ignition.
  • STEP 2: Choose the vehicle type on the scanner, then click the vehicle model and type of your vehicle.
  • STEP 3: Choose the diagnostics function and then select the control unit.
  • STEP 4: Choose the engine module. Once you see a variety of different options, select the option “special function”.
  • STEP 5: Under the special functions category, click on the” can crank relearn” option.
  • STEP 6: When you see the crank relearn section, select “ok to relearn”.
  • STEP 7: Start the ignition.

Special Notes: Only complete this function when the cam and the crank of the car have had a replacement. Different models and types require different processes of recalibrating.

So, whenever it is necessary, contact a professional to validate your exact model and type prior to making a selection. Your control unit will show everything about your vehicle.

The vehicle’s temperature must reach at least 70 degrees Celsius or above. If not, redo the complete process until the temperature is 70 or above.

Will disconnecting the battery reset the crankshaft sensor?

As a general rule of thumb, disconnecting the battery will clear out some codes. However, some codes must be reset by scanners/code readers, as mentioned in the steps provided above.

Questions and concerns about specific models and types can be directed to automotive repair services professionals who can offer more detailed instructions.


If you do not want to have serious problems with your vehicle after someone has tampered with or replaced the engine in your car, it is important that you relearn the crankshaft position.

Even though the process is not difficult, it is normally different based on the model and type of vehicle that you drive.

Following the appropriate steps, before you start your vehicle again, will not only eliminate unnecessary costly repairs but also save you time and frustration in trying to drive a car that may not start at all.

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