hey guys, so i have a 03 350z and my old ecu is jacked up. it keeps going into limp mode every time i go into high RPM's. so i ordered a nother one just like it. when the new one cam in it started my car and ran the first time but then when i tried to start my car the next day it cranks but doesnt want to turn over does anyone know what it could be? the weird thing is that the old ECU/ECM when i put it back in the car starts right away. do i need to go get it reprogrammed to my car or something? im lost here, i even got a new battery so it couldnt be the battery. please HELP!

 

Are you sure its the correct ecu? You probably need to get it reflashed at the dealer, not sure tho

 

NATS security and keys tied to ECU. Swap it out and yes, you need to get them reprogrammed.

 

okay so just go to the dealer and get it reprogrammed correct? i asked the dealer for a price and they said it would be around 150 to get it programmed. i just hope that works because that would be a waste of 150 if it doesnt fix the problem...

 

it most certainly has tp be reprogrammed. whether or not that actually fixes ypur initial problem os questionable.

 

but the weird this is, how come the car started the first time i put the other ECU in? but then after that it didnt do it again

 

If the dealers going to charge you $150 you might as well get an uprev reflash, you'll have some benefits besides just getting around the NATS issue

 

but if i get an uprev reflash will it start my car properly because its not starting at all

 

You can turn of NATS with Uprev. If NATS is indeed your issue causing the new ECU to not work (and I expect it is), an Uprev tuner can turn it off on your car as part of the tune. Then any copy of your key will work whether or not it has the security chip.