Fault code P0340 – a step-by-step guide to diagnosing and fixing it

P0340 is triggered by the engine control unit (ECU) when it detects a problem with the camshaft position sensor (CPS) circuit. The purpose of the CPS is to monitor the position and speed of the camshaft. It then transmits this information to the power control module (PCM). Based on this data, the PCM will regulate the formation of ignition sparks and the timing of the fuel injectors. If something interferes with the data transmission or the sensor malfunctions, the ignition process will be disrupted.

• CPS faults, such as a short or broken circuits and a damaged internal coil
• Damaged or corroded wires and connectors
• A defective PCM
• Sensor installation errors, causing transmission failure
• Oxidised electrical contacts
• Problems with the timing components

• The check engine light is on
• The engine runs rough
• A loss of engine power
• Stalling or misfiring
• Poor acceleration
• Starting difficulties

Checking the components:

• Inspect all of the wires and connectors for the device to make sure that there are no connectivity or conductivity issues.
• Check the DTCs by scanning the onboard computer with an OBD2 scan tool. The codes will help you to diagnose the problem. There could be more than one underlying cause, and the quicker they are identified, the quicker you will be able to remove the error. If you are unable to decipher them, there are several informative resources available on this topic online.
• Check the voltage of the camshaft position sensor using a digital multimeter. If the voltage is too low or no voltage is detected, there could be a problem with the device itself or a broken circuit. You can also test its signal output with an oscilloscope.

Fixing the components:

• Replacing the power cable and defective connectors can help to restore electrical power supply to the CPS and the transmission of important camshaft data.
• Sometimes the connectors can be repaired by removing contaminants and traces of oxidation using a specialised electrical contact cleaner for improved conductivity.
• If the device fails and cannot be repaired using these simple methods, the best option would be to replace it with a new one.