P0340 - How To Repair: Meaning, Causes, Symptoms, Fixes

P0340 - OBD2 Trouble Code Camshaft Position Sensor Circuit

Identical faults

The following faults are identical to P0340. For these, you can follow the information on this page:

P0345 – Camshaft Position Sensor “A” Circuit (Bank 2)

P0340 Code Definition

Camshaft Position Sensor “A” Circuit (Bank 1 or Single Sensor)

What Does the Engine Code P0340 Mean?

Character "P" in the first position the Diagnostic Trouble Code (DTC) represents the powertrain system (engine and transmission), "0" in the second position means that this is a generic OBD-II (OBD2) DTC. The "3" in the third character position in a DTC indicates that the ignition system is experiencing a malfunction or misfire has been detected. The last two characters "40" is the DTC number. OBD2 Diagnostic Trouble Code P0340 indicates that the Camshaft Position Sensor 'A' Circuit Malfunction in Bank 1 has been detected. The camshaft position sensor (CMP sensor) provides information regarding the rotational speed of the camshaft and where the camshaft is positioned in relationship to the crankshaft. If the Powertrain Control Module (PCM) can’t detect a signal from the camshaft position sensor, it will generate and store the P0340 trouble code.


    Carly Universal Scanner

    Carly Adapter
      iOS and Android enabled
      All car brands supported
      14-day money-back guarantee on the scanner
      Lifetime warranty with premium customer support
    Buy now

    What Is the Cause of P0340?

    While the most common causes of the P0340 code are faulty camshaft position sensor or circuit problems, P0340 can also be caused by other issues:

      A defective plug

      A defective cable connection

      A defective camshaft sensor

      A defective encoder wheel on the camshafts

      Incorrect control timings

    What Are the Symptoms of Code P0340?

    Symptoms of a faulty camshaft position (CMP) sensor:

      The vehicle starts badly or takes a while to start

      The motor runs with substitute values

      Rough idling, until the engine dies

      Poor throttle response when driving, jerking when accelerating

      Illumination of the check engine light (CEL), also called malfunction indicator lamp (MIL)

    Diagnostic background image

    How much does it cost to diagnose P0340?

    Visiting a car repair shop and letting them perform a diagnostics check can cost you $60-$100. For almost the same price you can get Carly. Its advanced features can cover what a professional automotive scanner that costs over $3,000 would, and more!

    Carly OBD2 Scanner

    Which Tools Are Needed To Diagnose P0340?

    To find out more about the P0340 code that is generated and stored in the Powertrain Control Module (PCM) of your car, the only tool you need is the Carly Universal OBD2 Scanner, which works for all car brands in the world with an OBD2 port. Carly is a revolutionary solution that allows you to access your car’s data with your phone and translates this information into powerful insights, predictions, and possibilities. This saves you trouble, time, and money.

    How To Diagnose and Clear the Code P0340?

    Performing a diagnostics check with a diagnostic scanner helps you identify a particular problem area that is outside the normal range and shows where a fault might be occurring. This helps you to detect errors before they cause more damage to your vehicle. In comparison to generic OBD devices that only provide OBD-level engine-related data, Carly can run advanced manufacturer-level diagnostics, check all your ECUs in your car (like ABS, airbag, multimedia) and get deeper insights. You can find additional information about the trouble code and understand the severity of the problem. With the new Smart Mechanic feature, you get additional professional insights and tips from expert mechanics. You are able to check components and their mechanics, find detailed repair tips, and learn about potential future damage. After you have fixed the problem you can easily clear the fault codes with Carly, too. Also, the diagnostic results are safely stored inside the app or as convenient PDF reports you can share with your friends or a mechanic.

    Common Mistakes When Diagnosing the P0340 Code

    The most common mistake is to look and try to fix each individual OBD2 code without having a holistic approach. Understanding the interrelationship of OBD-II (OBD2) systems is crucial to determining the root cause of the problem and finding the right solution. For example, it is very common to rush to replace the camshaft position sensor whenever the P0340 code appears. However, OBD-II (OBD2) code P0340 covers the entire circuit attached to the CMP sensor, including the electric wiring that is a very common cause of code P0340. Replacing the CMP sensor in case of circuit problems such as damaged wiring or loose connections won't solve the problem.

    How Serious Is Code P0340?

    OBD2 Diagnostic Trouble Code (DTC) P0340 is considered very serious. Besides leading to significant driveability issues, ignoring this code can result in further damages. P0340 fault code requires immediate attention and it is therefore recommended to have this code properly diagnosed and the problem solved as soon as possible.

    How To Fix the P0340 Code

      First, carefully check the plug connection of the camshaft sensor. To do this, disconnect the connector, check the sensor and the connector from the engine wiring harness. In particular, look for water ingress, oxidation, and defective pins. Once the plug has been removed from the sensor, the camshaft sensor can be checked with a multimeter. To do this, check the resistance of the sensor. If the value is very high, the sensor is defective.

      In most cases, the sensor itself is defective. The sensor is partially located in the cylinder head. Due to constant impact and heat, the plastic of the sensor becomes porous and the sensor can break internally. In some cases, the cable connections from the sensor can be defective. The exchange of the sensor should be possible at home if you have some technical skills. After the exchange, you should delete the error memory.

      If the error still occurs after replacing the camshaft sensor, it is necessary to check the encoder wheel on the camshaft. Damage may have resulted in incorrect measuring values by the sensor.

    Blurry background image
    Mobile and adapter showcase

    Estimated Cost of Repair for the P0340 Code

    Depending on the root cause of the issue, the costs of fixing the code P0340 can range from $100 to $1,000.

    Get Carly Now

    Learn More About the P0340 Code

    What Is a Camshaft Position (CMP) Sensor and What Does It Do?

    A camshaft position sensor (CMP) is essentially a component in the format of a cylinder, which is often located on the outside of the front cover (at the front of the engine under the valve cover). There, the sensor has the task of detecting the speed and the position of the camshaft. This is done by the sensor scanning a gear rim on the camshaft. This data is used by the engine control unit for precise fuel injection. When it adapts to the parameters accordingly the combustion is safe, effective, and environmentally friendly. Therefore, the precise function of the camshaft sensor (CMP) is very important in several respects.

    How to Reset and Relearn a Camshaft Position Sensor?

    In most cases learning the camshaft position sensor is not required. To reset the ECU disconnect the battery for ca. 30 minutes.

    *Every car is unique. The Carly Features that your car supports depend on the model, build year, hardware, and software in the car. Plug the scanner in the OBD2 port, connect to the app, run your first diagnostics, and check which features are available for your car. Also, keep in mind that any information provided on this website is for informational purposes only and should be used at your own risk. Mycarly.com is not responsible for any errors or omissions, or for the results stemming from the use of this information.

    Code list background

    Top 10: The most common OBD2 trouble codes

    Car Brands
    • BMW
    • Mini
    • Volkswagen
    • Audi
    • Seat
    • Skoda
    • Mercedes
    • Porsche
    • Renault
    • Toyota
    • Lexus
    • Ford

    Our Partners

    Inside of EU
    Outside of EU(priority shipping)

    Our payment methods

    (Depends on your country)

    Our advantages

    • Secure payment
    • Lifetime warranty on the Carly Scanner
    © 2023 Carly Solutions GmbH & Co. KG. All rights reserved