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SensorsSeverity Medium: diagnose soon

P0343Camshaft Position Sensor "A" Circuit High (Bank 1 or Single Sensor)

What it means

The camshaft sensor signal is too high: usually an open signal or ground wire, or a short to voltage.

Symptoms

  • Longer cranking before the engine starts
  • Occasional stalling or hesitation
  • Check engine light

Common causes

  • Faulty camshaft sensor
  • Wiring or connector fault
  • Missing 5 V or 12 V supply, or poor ground
  • Oil inside the connector (leaking sensor seal)

What to check first

  1. Scope cam and crank signals together and check their relationship
  2. Check the sensor supply and ground
  3. Inspect the connector for oil and corrosion
Can I drive with P0343? Usually yes for a short distance, but performance or economy may suffer and the fault can get worse. Diagnose it soon.

Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.

How to test the parts behind P0343

Camshaft position sensor (CMP)Wiring, typical values, multimeter and scope tests

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P0343: questions and answers

What does P0343 mean?

P0343: Camshaft Position Sensor "A" Circuit High (Bank 1 or Single Sensor). The camshaft sensor signal is too high: usually an open signal or ground wire, or a short to voltage.

What are the symptoms of P0343?

Longer cranking before the engine starts. Occasional stalling or hesitation. Check engine light.

What causes P0343?

Faulty camshaft sensor. Wiring or connector fault. Missing 5 V or 12 V supply, or poor ground. Oil inside the connector (leaking sensor seal).

How do you diagnose P0343?

1. Scope cam and crank signals together and check their relationship 2. Check the sensor supply and ground 3. Inspect the connector for oil and corrosion

Can I drive with P0343?

Usually yes for a short distance, but performance or economy may suffer and the fault can get worse. Diagnose it soon.