P0349

P0349 is the intermittent Bank 2 CMP A code - the signal disappears or goes invalid briefly under specific conditions (heat, vibration, RPM range, load) and recovers, so the customer gets a check engine light that comes on and off with no obvious driveability symptom, or a momentary stumble at a specific operating point. Cheapest-first ladder: data-log the Bank 2 CMP signal at high sample rate during a road test that replicates the customer's conditions, and log commanded vs actual VVT phaser angle alongside - P0349 paired with sluggish or erratic phaser response means the underlying problem is oil delivery to the cam phaser, not the sensor. Wiggle-test the harness from the Bank 2 sensor back to the PCM with the engine running, paying attention to where the loom crosses the cam cover or transitions through rigid plastic conduit. Heat-gun the sensor and the connector to provoke heat-soak failures. Inspect the cam cover gasket for weeping oil into the CMP connector - wet contacts cause exactly this kind of intermittent low/high signal flickering. Verify the sensor mounting bolt has not loosened and let the sensor walk in its bore, which changes the air gap dynamically with engine flex. The expensive misdiagnosis is replacing the Bank 2 CMP sensor when the real fault is timing chain stretch causing the cam to phase in and out of correlation under load - on high-mileage VVT engines, P0349 is often the early warning before harder P0016/P0017 cam correlation codes set in.

Vehicle-specific patterns: 2007-2014 Ford 3.5L Cyclone V6 P0349 is the early warning for stretched Bank 2 secondary timing chain - do the timing kit at this stage and save the engine, because letting it progress means a chain skip and bent valves. 2008-2013 GM 3.6L LY7/LFX throws P0349 as the Bank 2 oil control valve (OCV) screen progressively clogs and oil delivery to the rear cam phaser becomes inconsistent under load - OCV screen service plus a fresh oil change often clears it. 2011-2018 Chrysler 3.6L Pentastar P0349 typically clears with a Bank 2 OCV cleaning plus correct-viscosity oil; clogged screens are the dominant root cause. 2010-2016 Hyundai/Kia 3.3/3.8 Lambda V6 sees Hall-IC heat aging on the Bank 2 CMP where the sensor reads fine cold but goes intermittent above 200F coolant - heat-gun test confirms it in five minutes. 2007-2013 Nissan VQ35/VQ37 P0349 from valve cover gasket oil intrusion into the rear connector - the oil migrates along the wire shield and causes intermittent shorts. Estimated repair: $80 to $2,500.