P0346

P0346 means the Bank 2 Camshaft Position Sensor A signal is in range electrically but does not correlate properly with crankshaft position over the ECM's monitoring window - the pulse pattern arrives, but the cam-vs-crank phase angle drifts beyond the ~6 to 8 degree tolerance the PCM expects for that engine. This is a performance code, not a hard circuit failure (those are P0347/P0348), so the sensor itself is often fine. Cheapest-first ladder: scope the Bank 2 CMP signal during cranking and at warm idle - a healthy Hall-effect CMP produces a clean 0 to 5V square wave (some platforms 0 to 12V) with sharp edges and consistent pulse width matching the reluctor tooth profile; a VR (variable reluctance) sensor produces a sinusoidal AC waveform that grows from ~0.5V peak-to-peak at cranking to 3 to 8V at idle. Check the air gap with a feeler gauge (typical spec 0.020 to 0.050 inch). Inspect the reluctor wheel on the cam for chipped or oil-fouled teeth. Compare commanded vs actual VVT phaser angle on the scan tool - if commanded 25 degrees and actual reads 8 degrees, the cam is mechanically lagging the command, which throws P0346 even though the sensor is reading exactly what is happening. The expensive misdiagnosis is replacing the CMP sensor before checking for a stretched timing chain or worn VVT phaser that is creating a real cam-vs-crank offset - on high-mileage VVT engines (Ford Cyclone, GM LFX, Chrysler Pentastar, Nissan VQ), the chain or phaser is the actual fault and the sensor is just the messenger.

Vehicle-specific patterns: 2007-2014 Ford 3.5L/3.7L Cyclone V6 (Edge, Flex, MKX, Taurus, F-150) sets P0346 from stretched secondary timing chains on the rear bank that retard Bank 2 cam timing - listen for cold-start chain rattle and budget for a full timing kit because the chains, guides, tensioners, and VVT solenoids should all be done together. 2010-2016 Hyundai/Kia 3.3/3.8 Lambda V6 (Genesis, Santa Fe, Sorento, Sedona) throws P0346 from oil-control valve (OCV) screen clogging on Bank 2 - the rear-bank OCV sees less oil flow and clogs first; a screen service plus fresh 5W-30 often clears it. 2008-2017 GM 3.6L LFX/LLT (Camaro, Equinox, Traverse, Acadia) sets P0346 from worn Bank 2 cam actuators - the rear-bank phaser is buried under the intake manifold and gets neglected during routine service; full timing kit at 100k+ miles is the OE-pattern fix. Nissan VQ35/VQ37 (Altima, Maxima, 350Z/370Z) Bank 2 CMP gets oil-soaked from valve cover gasket weep and throws P0346 - replace the gasket and clean the connector before condemning the sensor. Estimated repair: $90 to $2,800.