Fault code P0343 – a step-by-step guide to diagnosing and fixing it

Error code P0343 is displayed and the check engine light is on - what does this mean?

The OBD/EOBD system detects a fault in the camshaft sensor circuit of bank 1, where a high signal has been detected. This DTC P0343 indicates problems with the camshaft sensor, its wiring or the engine control unit. The exact designation may vary for different manufacturers, but the error code always refers to the camshaft position.

What causes can this error code have?

• Defective camshaft sensor (CMP sensor)
• Damaged or corroded wiring to the sensor
• Loose or dirty plug connections
• Defective engine control unit (ECU)
• Interrupted ground connection of the sensor
• Dirty or damaged sensor ring on the camshaft
• Incorrect sensor voltage due to defective power supply
• Mechanical problems on the camshaft itself

What symptoms occur in parallel with error code P0343?

• Starting problems: The vehicle is difficult to start or does not start at all because the engine control unit cannot detect the camshaft position correctly.
• Irregular engine running: The engine runs out of round, stutters or has misfires, especially at idle or at low engine speeds.
• Loss of power: Significantly reduced engine power and poor acceleration as the injection and ignition cannot be optimally controlled.
• Increased fuel consumption: The engine consumes more fuel than usual due to faulty control of the injection valves.
• Check engine light: The yellow warning light in the dashboard lights up continuously and displays the stored trouble code.

How can the problem with fault code P0343 be rectified?

• Repairing fault code P0343 requires a systematic diagnosis of the camshaft sensor components.
• Replace the camshaft sensor: Replace the faulty CMP sensor with a new original part after checking the wiring and that it is in order.
• Repair wiring: Check all cables to the sensor for damage, breaks or corrosion and repair or replace defective cables completely.
• Clean plug connections: Disconnect the plug connection to the sensor, clean the contacts with contact spray and re-establish a secure hold.
• Clean the sensor ring: Remove dirt, oil or metal shavings from the sensor ring on the camshaft using a clean cloth and brake cleaner.
• Check the ground connection: Check the ground connection of the sensor on the engine and establish a secure, corrosion-free connection.
• Test the engine control unit: Have the ECU checked by a specialist workshop and reprogrammed or replaced if necessary.