Intermittent P0018 Code on 2009 Porsche Boxster S: Sensor or Mechanical Issue?

The P0018 code indicates a mismatch between crankshaft and camshaft position, specifically for Bank 2 Sensor A. This is often linked to mechanical issues such as a stretched timing chain or worn camshaft components.

Thanks for confirming—understanding the code's meaning helps clarify the root cause. However, I'm specifically asking whether a camshaft position misalignment could still allow normal engine operation. If so, it might point more toward sensor failure rather than mechanical issues like timing chain wear or phaser malfunction. I've already cleaned all electrical connections, but no improvement has been seen.

Have you tried cleaning the electrical connectors for the camshaft position sensors? Corrosion or loose contacts can sometimes trigger intermittent P0018 codes.

Hello Fentonp. P0018 - Crankshaft Position / Camshaft Position Correlation (Bank 2 Sensor A) This fault affects Bank 2, which is the second engine bank—excluding cylinder #1 (which belongs to Bank 1). This helps narrow down the issue to a specific component. Possible causes: - Timing chain stretched or timing belt skipped a tooth due to wear - Misalignment of timing belt/chain - Crankshaft or camshaft tone rings slipped or broken - Faulty crankshaft or camshaft position sensor - Damaged wiring harness to sensors - Damaged tensioner for timing belt/chain - Improperly torqued crankshaft balancer - Misbuilt or mis-timed engine - Loose or missing crankshaft balancer bolt - CMP actuator solenoid stuck open - CMP actuator stuck at non-zero position A dedicated OBD2 scanner is essential—basic code readers won’t provide enough detail. Freeze frame data will show the engine conditions when the fault occurs, which is critical for intermittent issues. I recommend focusing on Bank 2 inlet camshaft-related components such as the phaser, controller pulley, or chain tensioner—not just the timing chain itself—since a full chain failure would typically affect both cams and both banks. In your case, only Bank 2 is affected. Live data from the scanner can show actual vs. desired cam position. For best results, pull only two parameters: actual and desired camshaft position. Try to match engine conditions from freeze frame data—sometimes a sharp rev increase is needed to trigger the fault. Good luck! Feel free to ask questions if you need clarification.

Hello Fentonp. First, disconnect the solenoid or cam position sensor on Bank 2 inlet camshaft to verify whether it's the correct component being affected. Then, swap the Bank 2 inlet cam solenoid with a known good one from Bank 1 (if both are identical) and see if the fault moves—this will help determine if the issue is with the solenoid. Next, test the position sensor itself by swapping it with another sensor (e.g., from Bank 1). Perform a test drive until the P0018 code returns to isolate whether the sensor or its wiring is faulty. If the fault remains after these swaps, then the issue likely lies in the cam phaser, pulley, or chain tensioner—indicating a mechanical problem that may require engine disassembly. Always start with the position sensor as it's easier to access and test. Don’t worry—these tests won't damage your engine. Wiring issues like chafing or damage are also possible. Avoid overworking the system; wait for symptoms to worsen before acting. Good luck, and please share your findings—it could help others facing similar issues. Cheers, Peter.

Thanks for all the detailed advice! I'll follow through with the sensor testing and scanner data review. Will update here once I have results. Paul