06 Oct, 23

Faulty Crankshaft Sensor Symptoms: How to Identify and Address the Issue

The crankshaft sensor is a vital component of a vehicle’s engine management system. It plays a crucial role in ensuring smooth engine operation by monitoring the position and speed of the crankshaft. When this sensor fails or malfunctions, it can lead to a variety of issues that affect the performance and reliability of your vehicle. In this article, we will explore the common symptoms of a faulty crankshaft sensor, how to diagnose the problem, and what steps to take to address it.

Faulty Crankshaft Sensor

Section 1: Understanding the Crankshaft Sensor

Before diving into the symptoms, let’s briefly understand what a crankshaft sensor does. The crankshaft sensor is responsible for sending signals to the engine control module (ECM) to help determine the precise position and speed of the crankshaft. This information is crucial for ignition timing and fuel injection, ensuring the engine runs efficiently.

Read more: Common Symptoms And Solutions For Transmission Issues

Section 2: Common Symptoms of a Faulty Crankshaft Sensor

  • Engine Stalling: One of the most common symptoms of a faulty crankshaft sensor is random engine stalling. When the sensor fails to provide accurate data to the ECM, it may disrupt the engine’s fuel and ignition timing, causing it to stall unexpectedly, especially at low speeds or idle.
  • Hard Starting: A malfunctioning crankshaft sensor can lead to difficulties starting your vehicle. You may notice that the engine cranks longer than usual before firing up, or it may not start at all.
  • Poor Acceleration: If your vehicle experiences sluggish or uneven acceleration, it could be due to a faulty crankshaft sensor. The sensor’s inaccurate data can cause the ECM to deliver improper fuel and air ratios, resulting in reduced engine performance.
  • Check Engine Light (CEL): When the ECM detects irregularities in the data provided by the crankshaft sensor, it triggers the check engine light on your dashboard. Retrieving the diagnostic trouble codes (DTCs) with a scan tool can help pinpoint the issue.
  • Reduced Fuel Efficiency: A faulty crankshaft sensor can lead to inefficient combustion, causing a drop in fuel efficiency. You may find yourself making more frequent trips to the gas station.

Section 3: Diagnosing a Faulty Crankshaft Sensor

If you suspect a faulty crankshaft sensor based on the symptoms mentioned above, here are steps to diagnose the issue:

  • Scan for DTCs: Use an OBD-II scanner to retrieve DTCs from the ECM. Common codes related to crankshaft sensor issues include P0335 (Crankshaft Position Sensor “A” Circuit) and P0336 (Crankshaft Position Sensor “A” Circuit Range/Performance).
  • Visual Inspection: Check the sensor’s wiring harness and connectors for any visible damage or loose connections. Ensure that the sensor itself is securely mounted to the engine.
  • Measure Sensor Resistance: Use a multimeter to measure the resistance of the crankshaft sensor. Consult your vehicle’s service manual for the specific resistance values expected for your sensor.

Section 4: Addressing the Issue

If you’ve confirmed that the crankshaft sensor is indeed faulty, it’s essential to address the problem promptly to prevent further engine complications. Here are the steps to follow:

  • Replace the Crankshaft Sensor: Purchase a replacement crankshaft sensor that matches your vehicle’s make and model. Follow the manufacturer’s guidelines and torque specifications when installing the new sensor.
  • Clear DTCs: After replacing the sensor, clear the DTCs using your OBD-II scanner to reset the check engine light.
  • Test Drive: Take your vehicle for a test drive to ensure that the symptoms have been resolved. Pay close attention to engine performance and starting behaviour.
  • Regular Maintenance: To prevent future issues, adhere to your vehicle manufacturer’s recommended maintenance schedule. This includes periodic inspections and replacements of sensors as part of routine servicing.


1. What is a crankshaft sensor, and what does it do?

A crankshaft sensor is a component in a vehicle’s engine management system that monitors the position and speed of the crankshaft. It provides crucial data to the engine control module (ECM) for accurate ignition timing and fuel injection.

2. What are the common symptoms of a faulty crankshaft sensor?

Common symptoms include engine stalling, hard starting, poor acceleration, the illumination of the check engine light, and reduced fuel efficiency.

3. How can I diagnose a faulty crankshaft sensor?

You can diagnose a faulty crankshaft sensor by using an OBD-II scanner to retrieve diagnostic trouble codes (DTCs) from the ECM. Additionally, visual inspections of wiring and connectors and measuring sensor resistance with a multimeter can help diagnose the issue.

4. Can a faulty crankshaft sensor damage the engine?

While a faulty crankshaft sensor itself is unlikely to directly damage the engine, it can lead to poor engine performance and potentially cause further issues if left unresolved, such as engine stalling or misfires.

5. How much does it cost to replace a crankshaft sensor?

The cost of replacing a crankshaft sensor can vary depending on the make and model of your vehicle and whether you choose to do the replacement yourself or have it done by a mechanic. On average, the cost of the sensor itself ranges from $20 to $100, but labour charges may apply if you hire a mechanic.

6. Can I drive my vehicle with a faulty crankshaft sensor?

While it is possible to drive with a faulty crankshaft sensor, it is not recommended. A malfunctioning sensor can lead to unpredictable engine behaviour, including stalling and reduced performance, which can compromise your safety and the vehicle’s reliability.

7. Are there different types of crankshaft sensors?

Yes, there are various types of crankshaft sensors, including magnetic sensors, Hall effect sensors, and optical sensors. The type used depends on the vehicle’s make and model.

8. How often should I replace the crankshaft sensor as part of regular maintenance?

Crankshaft sensors are not typically replaced as part of routine maintenance. However, if you experience symptoms of a faulty sensor, it should be addressed promptly. Refer to your vehicle’s service manual for specific maintenance recommendations.

9. Can a faulty crankshaft sensor be repaired, or does it need replacement?

In most cases, a faulty crankshaft sensor should be replaced rather than repaired. Replacement ensures reliable sensor performance, and it is often more cost-effective in the long run.

10. Can I replace the crankshaft sensor myself, or should I seek professional help?

Whether you can replace the crankshaft sensor yourself depends on your mechanical skills and experience. If you are unsure or uncomfortable with the procedure, it is advisable to seek professional assistance from a qualified mechanic to ensure proper installation and diagnosis.

Remember that addressing a faulty crankshaft sensor promptly can help maintain your vehicle’s performance and prevent further engine complications. If you have specific questions or concerns about your vehicle’s crankshaft sensor, it’s always a good idea to consult with a mechanic or automotive expert.


A faulty crankshaft sensor can cause a range of problems, from engine stalling to reduced fuel efficiency. Recognizing the symptoms and taking prompt action to diagnose and replace the sensor can save you from costly repairs and keep your vehicle running smoothly. If you’re unsure about diagnosing or replacing the crankshaft sensor yourself, it’s advisable to seek professional assistance from a qualified mechanic. By addressing this issue promptly, you can ensure your vehicle’s reliability and longevity on the road.

Tags : Crankshaft Sensor, Faulty Crankshaft Sensor.
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