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P codepowertrainMedium severity

P0349Camshaft Position Sensor "A" Circuit Intermittent (Bank 2)

The signal from the bank 2 camshaft position sensor "A" cuts out or glitches intermittently.

Definition

P0349 sets when the PCM receives the bank 2 cam sensor "A" signal most of the time but detects sporadic dropouts, extra pulses, or momentary losses of cam/crank sync. Because the signal usually recovers, symptoms are often transient: occasional long cranks, intermittent stalling or stumbling (especially over bumps or at specific temperatures), momentary loss of VVT control, and an illuminated MIL. Intermittent cam signal faults are most often wiring and connector problems or a sensor failing with heat, and a random stall from signal loss makes this worth prompt attention.

Common causes

  • Chafed or fatigued wiring making intermittent contact with ground or breaking open under vibration
  • Loose, corroded, or oil-contaminated connector terminals
  • Cam sensor failing intermittently, often when hot
  • Metal debris on the sensor tip or a damaged reluctor causing extra/missing pulses
  • EMI from nearby ignition wiring inducing false pulses
  • Excessive cam endplay or reluctor runout varying the air gap

Common misdiagnoses

  • Replacing the crank sensor for the intermittent stall
  • Replacing the battery or ignition switch for the intermittent no-start
  • Replacing the sensor when the connector terminals are the fault
  • Replacing the PCM

Troubleshooting steps

  1. 1.Review freeze frame and stored history

    Note whether the fault sets hot or cold and at what RPM — heat-dependent sensor failures set warm, while vibration-related wiring faults often set over rough roads.

  2. 2.Wiggle-test the harness with the engine running

    Manipulate the sensor pigtail and harness while watching engine RPM and cam sync status; a stumble or sync-loss counter increment localizes the fault.

  3. 3.Inspect the connector and pigtail

    Look for oil intrusion from a leaking sensor seal, spread terminals, and cracked insulation where the pigtail flexes.

  4. 4.Record the signal with a scope over a drive

    Capture cam and crank channels while replicating the failure conditions and look for missing or extra cam pulses at the moment of the glitch.

  5. 5.Heat-test the sensor if wiring checks out

    A sensor that drops its signal when heated with a gentle heat source and recovers when cooled is failing internally.

  6. 6.Repair and verify over several cycles

    Confirm the fault stays gone across multiple hot restarts and a rough-road drive before releasing the vehicle.

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