P0017 OBD2 Code in Saturn Aura XR 3.5L: Cold Weather Trigger, Actuator Swap Failed

My 2008 Saturn Aura XR 3.5L has been showing P0017 fault code for several months. The issue appears specifically when the engine is cold (between 40-50°F). I've reset the code multiple times, and it disappears for a few weeks before returning. I recently replaced the Actuator Solenoid for Bank 1 Exhaust, but the problem persists. Given that only P0017 is present, not a cluster of related codes, I suspect an intermittent camshaft-to-crankshaft position issue rather than a major sensor failure. However, I'm unsure why this specific code appears under cold conditions and doesn't trigger other related faults. The vehicle is in excellent condition with only 40k miles, but the repair cost seems high relative to its value. Any insights or troubleshooting steps for P0017 on this model would be greatly appreciated.