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DTC code

P0340

Camshaft Position Sensor Circuit Malfunction

Technical guide

Symptoms

  • Hard start or no start
  • rough running
  • misfires
  • VANOS/VVT not functioning
  • check engine light

Probable causes

  • Camshaft position sensor circuit fault bank 1
  • failed CMP sensor
  • tone wheel damage
  • wiring fault
  • large gap between sensor and wheel

Diagnostic steps

  1. Check CMP sensor wiring and connector.
  2. Measure sensor (passive: 200-900 ohm; active: check supply voltage).
  3. Check air gap.
  4. Inspect tone wheel for damage.
  5. Replace CMP sensor.
Brand-specific notes (BMW, Hyundai/Kia)

BMW · BMW-MS41-65 · E36/E39/E46/Z3 · M52/M54

Symptoms

  • No start
  • rough running
  • misfires
  • VANOS not functioning

Probable causes

  • Faulty camshaft position sensor
  • damaged tone wheel on camshaft
  • wiring fault
  • gap too large between sensor and tone wheel

Diagnostic steps

  1. Check sensor wiring and connector.
  2. Measure sensor resistance.
  3. Check air gap between sensor and tone wheel.
  4. Inspect tone wheel for damage.
  5. Replace sensor.

Hyundai/Kia · i20/i30/Tucson/Rio/Ceed/Sportage · G4FA/G4FC/G4FG/D4FB all engines

Symptoms

  • Hard start or no start
  • rough idle
  • misfires
  • stalling
  • check engine light
  • possible CVVT/CVVD issues

Probable causes

  • Faulty camshaft position sensor
  • damaged CMP sensor wiring (common near valve cover)
  • failed timing chain tensioner causing timing variation (known on some Hyundai engines)
  • reluctor ring damage
  • connector pin corrosion

Diagnostic steps

  1. Check CMP sensor connector and wiring - route near valve cover prone to heat damage.
  2. Test sensor with multimeter.
  3. On G4FA/G4FC: check timing chain stretch (known issue) - listening for rattle on cold start.
  4. Replace CMP sensor.
  5. If timing chain stretched: replace chain, tensioner, guides.

Cross-checked technical synthesis (QA). It does not replace the manufacturer's procedure.

Models most reported with this code (NHTSA)

Nissan Altima 6Nissan Murano 6Nissan Maxima 5

Count of distinct owner complaints mentioning the code. US data — same engines, same failures.

AI here is a librarian: this page shows only what mechanics confirmed, or says “unknown”. It never suggests a diagnosis — MECCANIC interprets the code, never your car.

0 confirmed cases on P0340

Nothing confirmed yet for this code. No guess is offered on purpose.

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