it should be obd2, if so you can use a scanner, autozone will scan it for free, but since the car isnt running that doesnt help.
im pretty sure the maximas have the same style ecu that you can turn the dial to flash codes. but if you dont know where the ecu is, or how to do that, youre kinda fucked.

best bet might be to tow it to someone that knows what they are doing instead of selling you a starter you didnt need.