Nissan Repair: 03 Altima 2.5, crank angle sensor, fuel pressure regulator

Question
QUESTION: Hello. I am working on an 03 Altima 2.5. Car was towed into shop with a No Start. The other mechanic found a Code P0335 and I belive a P0340. Cam and Crank Sensor. He replaced the Sensors. Still doesnt start. Still get a P0335 KOEO. I pin tested the Connector. Battery Voltage on Red/Green. Black is good ground. The White wire has low voltage on it. The white wire is the ECMs Tach signal? When I crank the engine the scanner shows RPM. Less than 600 rpm with a weak battery.

Thanks

ANSWER: P0335 is a crank angle sensor code. Reasons that can cause no start -no spark are damaged CKP sensor connector, damaged reluctor ring (missing teeth or not turning), sensor output open, sensor output shorted to ground, sensor output shorted to voltage, failed crank sensor, but you replaced that, broken timing belt, failed ECU (or PCM) The white wire should have 5-8 volt reference voltage. The scanner tool may read RPM when crank the motor but the ECU may not respond. The ECU grounds the actuators, there shouldn't be external grounding to the body/motor/frame. Battery should retain 12.6 volts before running any tests. Make sure the distributor turns when the motor is cranking. Replace reluctor wheel and magnetic pick up assembly. Measure resistance at the ECU connector not the sensor connector. Sometimes testing for open or shorted wiring is difficult and requires time. If possible go to a Nissan dealer and get a wiring diagram for the ECU, it should be free. Hope this is of help  

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QUESTION: This is a strange problem. The Altima starts. But not every time. Now there is no codes in memory. I do have a theory. But I am not sure how the Nissan Security system works. When its not starting the Altima
Cranks, Has ignition spark. Has 50 PSI fuel pressure. Its almost like the Injectors arent firing.

Answer
Intermittent problems are hard to troubleshoot. The fuel pressure I believe it should be 37-39 PSI. Check fuel pressure regulator and solenoid. But I don't believe that's where the problem is. Most likely is the ECU. However, make sure that all the fuel injectors electrical connectors are clean! The BCM (Body Control Module), controls the security system. In rare cases,it will need to be reprogrammed by a Nissan technician. Depending on the security system, some BCM's they disable the ignition. My recommendation is to have an ASE or a Nissan certified tech look at the problem.