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A 2007 km Dongfeng Nissan Yida car with mileage of about 100 thousand km, equipped with electronic controlled engines and automatic transmission. User response: when starting the vehicle, the starter starts running, but the engine does not show signs. After receiving the car, during the start-up of the engine, it was found that the injector only injected 2~3 times, and the spark plug only jumped 1 times. Use diagnostic device for self diagnosis without fault code. Suspect or camshaft position sensor and its wiring is defective, so pull the plug down and run the engine. Plug the plug, remove the memory fault code P0335, test run, found that the acceleration is weak, the shift is slow, there is a clear file car phenomenon. Check the power cord and ground wire of the camshaft position sensor, normal. The signal waveform measured by the oscilloscope is normal. The connection between the engine control module (ECM) and the two sensors is checked with multimeter. Check the power line and grounding wire of ECM, normal. Replacement of ECM and cam position sensor is still in trouble. Further inspection shows that the tachometer of the dashboard is normal when the engine is running, but the engine speed data of the automatic transmission through the diagnostic instrument is abnormal and fixed to 385r/min. Check the line between ECM and automatic transmission control unit (TCM), normal. However, because the engine speed of ECM transmitted to TCM is abnormal, the signal of suspicion or camshaft position sensor is confused. The external elements have been checked, and the fault is suspected to be inside the engine, and the engine is decomposed. The result is that the variable intake timing regulator and the intake camshaft pin are deformed. The intake camshaft is cracked at the positioning pin and the chain guide is broken at the right time. Replace the damaged parts, replace the engine, run the engine, and eliminate the trouble thoroughly. The intake cam wheel location pin, the intake camshaft damage and the camshaft position sensor signal disorderly, ECM can not normally identify the signal, but also can not transmit the signal to the TCM, the engine can not start. When the engine is removed, the engine system is no longer referenced, so it can start the engine.