So a month ago it started raining pretty heavy where I live, my Z went into limp mode and I managed to get to my girlfriends house, a few days later my battery was dead and had a small puddle of water under it, I changed the battery for a new one and it worked just fine, the next day I started driving and it went into limp mode (the only code is P0605) I already swapped the ECU for 3 different ones (4 if you count the original one) and it keeps going into limp mode, any suggestions on what could it be?
My Z has a CAI, plenum spacer, headers, test pipes, y pipe, catback exhaust, chromoly flywheel and a stage 2 clutch, not sure if that’s relevant. Thanks!!

 

Did you pull codes?

 

The only code is P0605, I believe it’s a faulty ECU, but I’m getting that same code for the 4 different ECU’s

 

Time to look at all the harnesses.

https://www.autocodes.com/p0605_nissan.html

 

This, totally. ^^^

If the harness is bad/shorted, you can plug in 100 ECMs and still get the error. If that's not it, there might be a CAN error elsewhere that's part of the circuit.