P0340: Camshaft Position Sensor Circuit Malfunction

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One crucial part of an auto electrical system is the camshaft position sensor. However, car owners may experience some trouble points related to the system, giving off the P0340 diagnostic trouble code (DTC) or other similar errors. Read on and learn how to fix a P0340 OBD2 code” with appropriate diagnostic steps.

What Does Code P0340 Mean?

P0340 mean

While most persons are keen on knowing the symptoms, causes, and fixes of the P0340 code, it is crucial to understand this error properly. This fault code description represents a “camshaft position sensor (CMP) circuit malfunction.”

Thus, this fault could mean that the sensor is damaged or the electrical connections/wires have issues. The P0340 “camshaft position sensor A circuit bank 1” error encompasses the entire circuit. So, replacing the actual sensors might not be the solution to the problem since other components, including the powertrain control module (PCM), may be faulty.

Kindly note that this trouble code differs from a bad camshaft timing code. With this generic powertrain code, the powertrain control module may not receive the correct data for accurate control of engine parts.

When such signals from the cam sensor to the PCM appears broken, there is bound to be a failure in the fuel injector timing and ignition sparks. Thus, the car’s computer would store the code P0340, triggering the check engine light.

The effect of a P0340 code can be severe. Hence, it requires urgent attention to prevent possible damage to the engine. You should note that certain car models may need specific troubleshooting steps for diagnosis and repairs.

Symptoms of P0340 Trouble Code

With the drawbacks associated with a P0340 OBD-II trouble code, drivers should stop using the vehicle and look for a solution quickly. That said, the following are common symptoms associated with a code P0340.

  • Check engine light comes on
  • Stalling or rough running
  • Difficulties in starting the car
  • Engine misfires
  • Power loss while driving

Possible Triggers of Code P0340:

The car records an OBDII code P0340 due to any of these factors listed below:

  • Weak or dead battery
  • Broken or frayed wires or connectors within the circuit leads to poor electrical connection.
  • Damages powertrain control module
  • Defective PCM 
  • Weak starter motor
  • CPM faulty electrical connection
  • Open circuit
  • A defective camshaft position sensor
  • Open or shorted camshaft position sensor harness

How severe is a P0340 OBDII Code?

 The severity of this problem differs, as it varies from car to car. This error reading may prevent some vehicles from starting. Still, some drivers only start experiencing the symptoms (especially lack of power) when they hit the road.

If ignored for a long while, this error is expected to cause serious damage to other engine components.

Diagnosing a P0340 Trouble Code

diagonose P0340

 Expert mechanics employ effective diagnostic methods to find the root of this problem before concluding, as it helps determine the appropriate way to fix the error. Thus, you can diagnose this DTC following the steps below:

  • Kindly get a scan tool (a professional OBDII scanner would help) to retrieve the trouble codes that the PCM stores and read with an appropriate drawing. Also, look out for additional trouble codes.
  • Conduct a visual inspection of the CMP connector, ensuring that none is broken. A damaged harness from the camshaft sensor can also cause the dreaded P0340 error code
  • A glimpse through the circuit and wiring would help you detect frayed, shorted, corroded, or broken wires.
  • Test the battery voltage using a multimeter while the car is not running, and perform another when the car runs. If the values are below the expected range, you may need a replacement for the weak battery.
  • Scan the CMP voltage using an oscilloscope, and replace this car if the readings are abnormal.

Diagnostic Tools Needed:

  1. Basic hand tools
  2. Multimeter
  3. OBD 2 scanner
  4. An oscilloscope
  5. Car repair manual

Common Mistakes You Must Avoid When Diagnosing P0340

  • Investing in a new camshaft position sensor without inspecting the wiring and connectors within the circuit
  • Ignoring crankshaft sensor and engine misfiring issues
  • Not inspecting the reluctor ring

How to Fix P0340 OBDII Code?

A ‘camshaft position sensor circuit malfunction’ spells trouble; so, how do I fix error code P0340? Amidst the many factors that are likely to trigger the P0340 code, you can find the troubleshooting steps varying based on the car’s make, model, and year. 

Hence, the process of fixing a P0340 code for Ford may not be the same for fixing a P0340 code for Chevy on-board diagnostics. However, below are some common solutions for this problem.

  • Kindly replace the CMP circuit wiring or fix the circuit connector.
  • If the circuit wiring is in good condition, you should consider replacing the camshaft position sensor.
  • A reprogramming or replacement of the PCM would suffice.

Note: Dealing with this error code requires technical knowledge, and it would be best to take reach out to an auto repair shop for a skilled technician to handle it.

How Can I Avoid a P0340 OBD2 Error in the Future?

A periodic replacement of the camshaft position sensor even when it is still in good condition (over five years) can help avoid this issue. This regular maintenance schedule can prevent a P0340 code from popping up in the future.

It is also helpful to conduct regular oil changes to cool the engine and prevent overheating from damaging such electronic components.


How is P0340 diagnosed?

 You can diagnose a P0340 error code using an appropriate diagnostic tool. After that, you can check the circuit to find the fault, ranging from frayed wires to broken connectors between the CMP sensor and PCM.

Where can I find my car’s “camshaft position sensor A circuit Bank 1?”

 You would find the CMP sensor A circuit bank 1 sitting beneath the timing belt where the camshaft sensor mounts. 

How does one fix a camshaft position sensor?

 Start by disconnecting the battery’s negative cable before moving further to find the sensor. As you release the tab above the sensor, get the wires and mounting bolt disconnected. Pull off the sensor and affix the new one with a slight twist. 

Final Thoughts

 A P0340 DTC indicates a problem related to the vehicle’s timing. Modern vehicles’ on-board diagnostic 2 systems will often detect such issues by monitoring the signal from the ignition lock cylinder to the fuel injection control module and crankshaft position sensor. Read through this piece to learn how to fix a P0340 OBD 2 code.

how to test & fix p0340 camshaft position sensor circuit malfunction
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