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Jay, Nissan Technician
Category: Nissan
Satisfied Customers: 19057
Experience:  20+yrs experience with Nissan & Infiniti Trained & Certified.Currently still working for Dealer
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2001 Nissan Sentra: I tell if the ecu..quit running..start condition

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How can I tell if the ecu is bad on my 2001 Nissan Sentra? The car quit running suddenly and I have not been able to get it running again. An auto electrician checked the ecu out for me and stated that the ecu was not communicating with the engine FI system, thus the no start condition. However, he seemed not too sure about what he was telling me. The engine seems to want to start and almost does, but it just doesn't get to the point of running on its own. I haved checked all connections on all sensors and have sprayed sesnor conductivitiy cleaner on all harness connectors, all to no avail. I pulled the ecu and see that it is a "3N" model with the following #'s----5ZE13N-----JA56R08 B84 1402. The car has 75,000 mi on the odometer. Can you help? art
Hello and thank you for using

If you have a Ecm issue, then what most likely happens is the scanner can not communicate with the Ecm. From that point you check the circuit from the OBD2 connector and check power and wire continuity to the Ecm. If all that checks out, then you have verified that the Ecm is indeed bad. Here is the wiring diagram for the OBD2 connector to help diagnose if your Ecm is indeed bad or not, or if you have a simple wiring problem.graphic

If you have any more questions on this, please feel free to ask. Thanks Jay!
Customer: replied 6 years ago.

Jay----thanks for your reply. I have some additional questions for you. Here they are:

* Is ECU failure that common? This is the first vehicle that I have ever experienced this


* I do remember the electrical tech telling me something about his laptop not been able to communicate with the ECU--I understood that the ECU was not communicating with FI system on the engine. I guess the tech never got past the ECU itself. He did mention that all harnesses had checked out and were conducting siganals back and forth. But as I said, the tech did not seem to be sure of his diagnosis and I did not want to spend on the cost of an ECU if that was not the prob.

* Where would you recommend that i purchase an ECU? Would you recommend new, used or rebuilt?

* Am I looking at ECU failure again with this vehicle?

Your reply is appreciated and thanks for the wiring diagram---art


I have seen Ecm failures with communication on the early 2000's Sentra's. Where customers will come in for a check engine light and the scanner could not communicate with the computer to get the code. I would recommend getting the proper one for the car using the vin number. There are many different Ecm numbers, so I would recommend you get it from the dealer using the vin number so you get the correct one for the car. I don't know of any place that can repair Ecm's. Even still, the ones I have seen that customers have sent out for repair, normally come in and end up needing a Ecm any way.

If you have any more questions on this, please feel free to ask. thanks Jay!
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