Most cars have one camshaft position sensor per camshaft. The exact number depends entirely on the engine's design. A common single overhead camshaft (SOHC) engine, often found in 4-cylinder cars, will typically have one sensor. A double overhead camshaft (DOHC) engine, standard in many V6 or V8 configurations, will have two—one for each camshaft. Some high-performance or complex engines may have even more. This sensor is critical, as it monitors the camshaft's position and speed, sending this data to the engine control unit (ECU) to precisely time fuel injection and ignition spark for optimal performance and efficiency.
The primary role of the camshaft sensor is to work in tandem with the crankshaft position sensor. While the crankshaft sensor tells the ECU the position of the pistons, the camshaft sensor identifies which cylinder is on its intake or exhaust stroke. This allows the ECU to fire the correct spark plug and inject fuel at the exact right moment. A failure in this sensor can lead to immediate drivability issues.
Common symptoms of a failing camshaft sensor include:
- Engine stalling or rough idling
- Difficulty starting (the car may crank but not start)
- A noticeable loss of engine power and acceleration
- Poor fuel economy
- The illumination of the check engine light
| Engine Configuration | Typical Number of Camshafts | Typical Number of Camshaft Position Sensors | Common Vehicle Examples |
|---|
| Inline 4-Cylinder (SOHC) | 1 | 1 | Honda Civic, Toyota Corolla |
| Inline 4-Cylinder (DOHC) | 2 | 2 | Ford Focus, Hyundai Elantra |
| V6 (DOHC) | 4 | 2 | Ford F-150 (3.5L EcoBoost), Toyota Camry V6 |
| V8 (DOHC) | 4 | 2 | Chevrolet Silverado (5.3L V8), Ford Mustang GT |
| V8 (Pushrod) | 1 | 1 | Chevrolet Corvette (LT1), Dodge Charger (5.7L Hemi) |
Replacement complexity and cost vary. On some transverse-mounted engines, the sensor(s) are easily accessible, making it a straightforward DIY job. On others, it may require significant disassembly, best left to a professional mechanic.
