Yes, a faulty camshaft sensor is a common cause of a car not starting. This sensor, more accurately called the camshaft position sensor (CMP), is critical for engine operation. It tells the engine control unit (ECU) the exact position of the camshaft, which in turn determines the position of the intake and exhaust valves. Without this precise data, the ECU cannot correctly time the fuel injection and ignition spark. This often results in the engine cranking (you hear the starter motor turning) but failing to actually fire up and run.
The most definitive symptom is a crank-no-start condition. The engine will turn over but won't catch. You might also experience an extended cranking time before the engine reluctantly starts. In some cases, the ECU might detect the sensor's failure and trigger the check engine light, often storing diagnostic trouble codes like P0340 (Camshaft Position Sensor Circuit Malfunction) or P0345 (Camshaft Position Sensor Circuit Bank 2).
| Symptom | Description | Likelihood of Causing No-Start |
|---|
| Crank-No-Start | Engine turns over but does not fire. | Very High |
| Extended Cranking | Engine takes much longer than usual to start. | High |
| Check Engine Light | Illuminated dashboard warning. | High |
| Engine Stalling | Engine may start but then immediately die. | Medium |
| Rough Idle | Engine runs unevenly if it does start. | Low |
| Loss of Power | Noticeable decrease in engine performance. | Low |
Diagnosing this issue typically involves using an OBD-II scanner to check for relevant fault codes. A mechanic can then test the sensor's electrical output with a multimeter to confirm it's faulty. Replacing a camshaft sensor is generally a straightforward repair, but its location can vary from easily accessible to buried under other components, affecting labor time and cost. If you're experiencing a no-start situation, the camshaft sensor should be high on the list of suspects to be checked.
