The 2008 Toyota Sienna uses two camshaft position sensors, one on each bank of its V6 engine. This article explains how many sensors there are, where they sit, and what that means for maintenance and diagnosis.
Engine context
The 2008 Sienna is powered by a 3.3-liter V6 engine (commonly from the 1MZ-FE family) with variable valve timing. To manage timing across both camshafts, Toyota typically employs a camshaft position sensor on each bank. This dual setup helps the engine control module monitor cam position and synchronize fuel and ignition as the valves open and close.
Camshaft position sensor count and placement
Before listing the key facts, here's what to know about the sensors on this model:
- There are two camshaft position sensors in the 2008 Sienna—one on each cylinder head bank (left and right).
- Each sensor monitors a camshaft to provide timing data to the engine control module for the VVT-i system.
- Both sensors are mounted near the front of the engine, adjacent to the cylinder heads behind the valve covers. Access typically requires removing some components for inspection or replacement.
Having a sensor on each bank ensures accurate timing information across the entire engine, supporting smooth operation and reliable starts.
Diagnosing camshaft sensor issues
If you’re diagnosing potential CPS problems, consider common symptoms and maintenance steps. The Sienna may exhibit rough idle, misfires, stalling, or a check engine light related to cam timing when one or both sensors fail or have wiring issues.
- Rough idle or intermittent engine misfires, particularly at idle or during takeoff.
- Engine stalling or failing to start in some conditions.
- Check engine light with codes related to cam timing or sensor circuits.
- Symptoms may involve the sensor harness or connectors, so inspect wiring as well as the sensor units.
If these symptoms appear, have a mechanic test both CPS units and their wiring, as well as the timing components.
Summary
Answer: Two camshaft position sensors in a 2008 Toyota Sienna, one for each bank of its V6 engine. They are located near each cylinder head and provide timing data to the engine control module to support VVT-i. Regular inspection and careful replacement can prevent timing-related drivability issues.