P1345

P1345 is the Camshaft Position to Crankshaft Position correlation code — the PCM compares the cam sensor pulse position relative to the crank sensor reference pulse and, on GM LS and LY7 platforms, expects them to align within a window of roughly ±5 to ±8 crank degrees depending on calibration. When the measured offset drifts outside that window across multiple revolutions, P1345 sets. Cheapest-first: scan-tool the Cam Retard Offset PID at idle warm (should be within ±2 degrees of zero on LS V8s) and the Camshaft Position Actual vs Desired on VVT engines (should track within ±3 degrees); if the offset is steady but out of range, the timing chain has jumped a tooth or the reluctor wheel on the cam gear has shifted (a known LS failure where the cam reluctor's press-fit walks). If the offset oscillates randomly, you have a sensor or wiring issue. The expensive misdiagnosis here is replacing cam and crank sensors when the real cause is timing chain stretch — on a 100K-mile LY7 with P1345 and a steady -6 degree cam retard offset, you need a chain set, not sensors.

Vehicle-specific patterns: 2007-2009 Acadia/Outlook/Enclave/Traverse 3.6L LY7/LLT is the most documented P1345 platform — primary timing chain stretch is so common GM issued PI0729 and extended the warranty on early VINs; the smoking gun is cam-retard offset trending more negative as miles accumulate. 1999-2007 Silverado/Tahoe/Suburban 4.8L/5.3L/6.0L LS sets P1345 when the cam reluctor wheel walks rearward, throwing off the sensor's tooth alignment. 2008-2012 CTS 3.6L LLT throws P1345 from the timing chain guide failure documented in PIP4830. 2010-2015 Camaro 3.6L LFX gets P1345 from the same chain stretch family. Estimated repair: $180 to $2400.