i got this code out of the computer ECU 5 long 4 short
the result is

Automatic Transmission Control Unit Signal to ECU

i also got one for the knock sensor

 

dont stress the Knock sensor yet. It tends to be a tattle tell of sensors. Once one goes off it goes off, its kind of the little ***** of the car. As far as your other one. lemme check


DTC 0504

Diagnostic Trouble Code 0504 points to a problem with the Automatic Transmission Communications line.
Pulse signals are exchanged between the Engine Control Module and the Transmission Control Module to assure
smooth shifting during hard acceleration or deceleration.

This malfunction is detected when the ECM continuously receives an incorrect voltage from the TCM.
Possible causes include...
- Harness or connectors (The communications line circuit between the ECM and the TCM is open or shorted.)
- TCM
- Discharged or faulty battery


Now I dont know what it all means, but it looks to be a automagical problem in you thingy.

 

Your transmission triggered a fault in the transmission computer, sending the code to the ECU. This could be caused by hard acceleration or deceleration, or some type of problem(s) with shifting of the gears. You can clear your ECU and the codes should disappear. You can also extract any codes in the transmission computer to give you an exact code of what went faulty. The process is lengthy, but it is worthwhile just in case your curious. If you have access to a Hayne's manual, you can find the process explained on pages 7B-2 and 7B-3. Did your Overdrive lamp "flash" in any way?