No, a car cannot run properly or may not start at all without a functioning camshaft position sensor. This sensor is critical for the engine's computer to correctly time fuel injection and ignition spark. Without its signal, the engine control unit cannot synchronize the engine's operation, leading to immediate starting failure or, in rare cases, extremely rough operation that could cause further damage.
The camshaft position sensor (CMP) provides real-time data on the position of the camshaft. The engine control module (ECM) uses this information, along with data from the crankshaft position sensor, to determine the precise moment to fire each spark plug and inject fuel into the cylinder. This synchronization is vital for efficient combustion, power, and emissions control.
If the CMP fails, you'll typically experience one or more of these symptoms:
- Failure to Start: This is the most common outcome. The ECM doesn't receive a signal to initiate fuel injection and spark, so the engine will crank but not start.
- Engine Stalling: A failing sensor might cause the engine to stall intermittently while driving, which can be a significant safety hazard.
- Poor Performance: The engine may run very rough, misfire, hesitate, or lack power due to incorrect timing.
- Illuminated Check Engine Light: The ECM will detect the fault and store a diagnostic trouble code (DTC), such as P0340 (Camshaft Position Sensor "A" Circuit Malfunction).
While the crankshaft position sensor is the primary signal for engine speed and piston position, the camshaft sensor provides the "phase" information needed to distinguish between intake and exhaust strokes. Some very basic engines might run in a degraded "limp mode" using only the crankshaft sensor, but performance will be severely compromised, and it is not a sustainable solution. Driving without a working camshaft position sensor is not recommended as it can lead to poor fuel economy, increased emissions, and potential damage to the catalytic converter from unburned fuel.
