Anyone had 0504-A/T Control Unit Signal to ECU?
Did you get any other ECU codes along with it?
How did you fix it? Reset ECU? Replaced TCM?
Is TCM something that only dealer should replace?

Knock sensor - could a used one be any good? Is it even worth trying?

I know I have many questions. I also did search for all these and found some good answers but not to these specific questions.

Thanks much!

 

i believe i had this code on my car and I came up with a at 504 comm line and knock sensor and speed sensor. I read up in the Nissan database that two things could be wrong. Few Maximas are having a problem with the speedomoter, thats its not sending a proper signal, or that it could be the engine harness that bends over the rear valve cover ( some people had the harness crack and whatnot)
Just to make sure I will look up this code for you at work today and let you know tonight.


Mike

 

Thanks Mike. I really appreciate it.