One habit I’ve developed throughout my 18 years of driving and fixing my cars is to always perform a reset/relearn/calibration after replacing or fixing any problem that caused an error code or a warning light to come on the dashboard.
The essence of the reset is to enable the car’s ECM to start using information from the replaced or fixed parts to ensure the smooth running of the engine.
However, for the crankshaft position sensor to start working well after a no-start or replacement, you may need to perform a crankshaft position sensor relearn/reset. So, how do you reset the crankshaft position no start?
Can Crankshaft Position Sensor Cause No Start?
Yes, a faulty crankshaft position sensor can indeed cause a no-start condition in a vehicle because the sensor is responsible for providing information about the position and speed of the crankshaft to the ECM, which is important for proper ignition timing and fuel injection timing.
If the CKP sensor fails or malfunctions, the ECM/PCM may not receive accurate data about the crankshaft’s position and speed. As a result, the engine may not receive the correct timing signals for ignition and fuel injection, leading to a no-start condition.
Moreover, some vehicles rely on the crankshaft position sensor signal to enable the fuel pump to deliver fuel to the engine, so a faulty crankshaft sensor can also prevent fuel delivery to the engine.
Common symptoms of a faulty crankshaft position sensor that can lead to a no-start condition are:
- The engine cranks but does not start.
- Intermittent stalling or sudden engine cut-off while driving.
- Engine misfires.
- Difficulty starting the engine, especially when hot.
- Check Engine light is illuminated, with diagnostic trouble codes related to the crankshaft position sensor (e.g., P0335, P0336).
How to Reset Crankshaft Position Sensor No Start
Here’s a step-by-step guide on how to reset the crankshaft position sensor no start:
Step 1: Prepare the Vehicle for a Reset
The first step is to reset the crankshaft position sensor no start is to make sure the vehicle is parked in a safe location with the transmission in Park (for automatic transmissions) or Neutral (for manual transmissions).
Do not forget to turn off all accessories, and put the ignition key in the Off position.
Step 2:Locate the OBD-II Port
The next thing to do is to locate the OBD-II port in your car which is usually located under the dashboard, on the driver’s side of the vehicle with 16 pins.
It may be concealed by a cover that you’ll need to remove. So look properly. Immediately you find the port, plug your diagnostic scanner into the port.
Step 3: Power On the Scanner
After plugging the scanner into the OBD-II port in your vehicle, the next action is to turn the scanner on by pressing the power button or following the scanner’s manufacturer’s instructions.
The scanner may prompt you to input certain vehicle information, such as the vehicle VIN, make, model, and year of the vehicle.
Step 3: Establish a Connection
Once the scanner is powered on, it will establish a connection with the vehicle’s onboard computer system (ECM or PCM).
You should now follow the on-screen instructions provided by the scanner to select the appropriate vehicle protocol and establish communication.
Use the arrow keys or touchscreen on the scanner to navigate through the menu options.
- Start by selecting ‘diagnosis’
- Select control unit
- Select the ‘power train’, and
- Select the ECM (Engine control module) and allow it to run.
Look for a section related to “System Tests,” “Relearn Procedures,” or “Special Functions.” The exact wording may vary depending on the scanner model.
Step 4: Select Relearn Procedure
Within the menu, locate and select the option for performing a crankshaft position sensor relearn procedure. It may be listed as “CKP Sensor Relearn,” “CKP Sensor Reset,” ” cam crank relearn,” or something similar.
Click on it to start the resetting process. Once you’ve selected the relearn procedure option, the scanner will provide you with step-by-step instructions on how to proceed. Follow these instructions carefully.
You may be asked to turn the ignition key to the On position without starting the engine or start the engine. Just do as you’ve been instructed by the scanner and monitor the resetting process.
Also, during the relearning procedure, the scanner will display various engine parameters and monitor the CKP sensor signal. You must ensure to follow the scanner’s instructions and monitor the readings to ensure the procedure progresses.
Step 5: Complete the Resetting Procedure
Once the relearn procedure is complete, the scanner will display a confirmation message indicating success. Once this is displayed, you’re urged to follow any final instructions provided by the scanner, such as turning off the ignition or disconnecting the scanner.
Nevertheless, after completing the relearn procedure, the ECU will get rid of any error code relating to the crankshaft position sensor stored in its system.
You can also use the diagnostic scanner to clear any other fault codes stored in the ECM or PCM memory to ensure that any previous fault codes related to the crankshaft position sensor no start problem are properly cleared.
Once this is done, start your car and take the vehicle for a test drive to confirm that the crankshaft position sensor is functioning correctly and that the engine operates smoothly.
What to Do Before Resetting Crankshaft Position Sensor
Here’s what to do before resetting the crankshaft position sensor:
Diagnose the Problem
If you’re experiencing a no-start condition related to the crankshaft position sensor, it’s more likely that the sensor itself needs to be diagnosed, repaired, or replaced. In fact, it should be replaced. I don’t believe it’s worth fixing or repairing a crankshaft sensor that has gone bad.
However, before starting the replacement, you need to first use a diagnostic scanner to read any trouble codes stored in the engine control module (ECM) or powertrain control module (PCM). This is because a no-start condition can have various causes, and the CKP sensor is just one possibility.
Common codes related to crankshaft position sensor issues include P0335 (CKP sensor circuit malfunction) or P0336 (CKP sensor range/performance problem).
Check the Crankshaft Position Sensor for Any Damages
Inspect the sensor and its wiring harness for any visible signs of damage, corrosion, or loose connections. During the inspection, ensure that the sensor is properly mounted and aligned with the crankshaft.
Some vehicles use a reluctor ring mounted on the crankshaft or flywheel to provide input to the CKP sensor. So, if that is the case for your vehicle, inspect the reluctor ring for any damage or missing teeth that could affect the sensor’s operation.
You can also use the opportunity to clean any dirt or debris that may be obstructing the sensor and its wiring harness.
Use a Multimeter to Test the Sensor
Use a multimeter to test the CKP sensor’s resistance and voltage output according to the manufacturer’s specifications. If the sensor is not within the specified range, it may be faulty and need replacement.
With the ignition turned on (but the engine not running), use a scan tool to monitor the sensor’s signal. Crank the engine and observe whether the signal is being generated properly.
A lack of signal or erratic signal could indicate a problem with the sensor, wiring, or reluctor ring.
Replace the Sensor
If after doing this series of tests it reveals that the crankshaft sensor is faulty, you will need to replace it with a new one immediately.
While doing the replacement, ensure that the replacement sensor is compatible with your vehicle’s make, model, and engine.
Don’t just go and buy a sensor that is not suitable for your engine for your car. This is what you should do before resetting a no-start problem caused by a faulty crankshaft position sensor.
Conclusion
Since it has already been established that a bad/faulty crankshaft position sensor can cause a no-start problem, you can reset the sensor after replacing it with a new unit by either using a diagnostic scanner tool (OBD-II Scanner) or disconnecting the battery.
However, the best method to perform the relearn is by using an OBD-II scanner and following the procedure explained in this article.
