The DTC P0340 is associated with the engine’s camshaft position sensor, specifically pointing towards potential malfunctions in the “A” circuit of bank 1. The camshaft position sensor is instrumental in monitoring the position of the camshaft, allowing the Engine Control Module (ECM) to optimize engine timing. When the ECM receives irregular or absent signals from this sensor, it recognizes a discrepancy and sets the P0340 diagnostic trouble code which can be determined with diagnostic scanners.

More about the code

Having a compromised camshaft position sensor can lead to a host of performance issues in the vehicle. This sensor helps in the precise timing of fuel injection and ignition, ensuring optimal combustion. When the signal is faulty or missing, the vehicle might experience rough idling, difficulty starting, stalling, or decreased fuel efficiency. The risks exist of more severe engine issues if this code will not be addressed promptly. “Check engine light” (CIL lamp) is normally light on at the driver’s dashboard and engine operation isn’t smooth until this code stays active.

What are The Causes of Code P0340?

Delving into the technical reasons behind this code, several potential culprits emerge:

  1. Faulty Camshaft Position Sensor. The sensor itself might be malfunctioning or might have gone bad, leading to inaccurate or missing signals.
  2. Wiring and Connector Issues. Damaged wires, corroded connectors, or poor connections in the sensor’s circuit can interrupt the signal transmission.
  3. Timing Belt or Chain Problems. If the timing components, such as the belt or chain, are worn or misaligned, they can affect the camshaft’s position, thus causing discrepancies in the sensor readings.
  4. Metallic Debris. Sometimes, metallic fragments can accumulate on the sensor due to its magnetic nature, obstructing its ability to read the camshaft’s position correctly.
  5. ECM Issues. On rarer occasions, the problem might lie with the Engine Control Module itself, either due to software glitches or hardware malfunctions.

DTCs Related to P0340

P0300, P0335, P0336 – P0339, P0341, P0342, P0343, P0344, P0345, P0346 – P0349, P0725.


A rough average for a straightforward camshaft position sensor replacement would be between $90 and $600. However, if additional repairs are required, the costs can exceed this range.

Driving with a P0340 code is not advisable for the reasons of the engine performance, reduced fuel efficiency, increased emissions, safety measures and potential for engine damage.

Dirty oil can be a contributing factor to conditions that may set off a P0340 code, but it’s not typically the direct cause of a camshaft position sensor malfunction.

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