P0340 OBD-II Trouble Code: Camshaft Position Sensor Circuit Malfunction

Check Engine Light

P0340 code definition

Camshaft Position Sensor Circuit Malfunction

What the P0340 code means

The camshaft position sensor calculates the rotational speed of the camshaft and where the camshaft is positioned in that rotation. The camshaft sensor sends a signal to the Power Control Module (PCM) to communicate this information. The PCM then uses the information collected by the camshaft position sensor to set the fuel injector timing and control the ignition spark.

When the signal to and from the camshaft position sensor and the PCM is broken, the ignition spark and fuel injector timing will fail and the PCM will store the P0340. This will trigger the illumination of the Check Engine Light.

What causes the P0340 code?

  • A camshaft position sensor circuit wiring that is broken, shorted, or corroded
  • A camshaft position sensor circuit connector that is broken, shorted, or corroded
  • A faulty camshaft position sensor
  • A failed crankshaft position sensor
  • A faulty PCM

What are the symptoms of the P0340 code?

  • The Check Engine Light will come on
  • The vehicle may not start, or may be difficult to start
  • The vehicle may idle rough or stall
  • The vehicle may misfire
  • There may be a loss of power while driving

How does a mechanic diagnose the P0340 code?

  • Uses an OBD-II scanner to retrieve all of the trouble codes that have been stored by the PCM

  • Inspects the camshaft position sensor wiring for wires that are broken, corroded, or shorted

  • Inspects the camshaft position sensor connector for connectors that have broken or corroded

  • Inspects the camshaft position sensor circuit wiring for wires that are broken, corroded, or shorted

  • Checks the continuity of the camshaft position sensor circuitry

  • Completes any necessary repairs for other related trouble codes that have been stored by the PCM

  • Uses a scan tool or oscilloscope to check the camshaft position sensor voltage readings

  • If the voltage readings are abnormal, the camshaft position sensor will need to be replaced.

  • If the voltage readings for the camshaft position sensor voltage readings are normal, it is possible that there is a problem with the PCM which may require replacing or reprogramming.

Common mistakes when diagnosing the P0340 code

Before replacing the camshaft position sensor, it is important to inspect the wiring and connectors to rule them out as the cause of the problem. This is the most common mistake when diagnosing the P0340 trouble code.

Another mistake that is made during the diagnostic procedure is neglecting to consider a misfiring problem or a crankshaft sensor problem as possible sources of the P0340 trouble code.

How serious is the P0340 code?

This code is considered serious. The car may not start or be difficult to start. While operating the vehicle, the driver may also experience a lack of power. These symptoms make the operation of the vehicle dangerous for the driver and anyone else on the road. It is also possible for damage to be caused to other components in the engine if the P0340 trouble code goes unaddressed for an extended period of time. The P0340 trouble code should be diagnosed and repaired immediately.

What repairs can fix the P0340 code?

Additional comments for consideration regarding the P0340 code

The P0340 trouble code is not always easy to diagnose. Be sure to check the system in its entirety before making any determinations. Also be sure that you are repairing and/or replacing the right component.

Need help with a P0340 code?

YourMechanic offers certified mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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