I had the P0505 ECM Failure problem with my 01 Maxima SE. I've unplugged the motor mounts, I replaced the Idle Air Control Valve + Gasket, and my junkyard ECM just came in the mail today. I have to bring it to the dealership to have it flashed, IAC relearn, and TPS calibrated (because I ****ed it all up during the job). But I also might need them to rewire a new harness in there. The harness itself looks pretty burnt and the wires don't look like their in the best shape. What should I do in this position? I don't want to put in the working ECM just to have it break again because the wires are bad.

 

 

Your photo shows that the wires got hot and melted the plastic connector. The connector may or may not be usable, it depends on if the wire connector inside is still in position to make contact.

The wires themselves are an unknown to me, no picture. Did the insulation melt off and leave you with bare wire? If yes, that can be re-insulated with tape or shrink wrap.

But what can happen that will require the wires to be replaces is if the wires got hot enough to almost melt, the wires will have crystallized and become brittle. Besides being susceptible to breaking, the wire will have lost much of its conductivity.

If you are taking it to the dealer, have them examine it. They do have replacement harness ends.