I had a Hayden 405 tranny cooler installed 2 weeks ago. Today I got an 0504 code from my ECU. I checked it out and it says: Automatic Transmission Control Unit Signal to ECU. Does anyone have any experience with this code? I'm suspecting it may be from the tranny cooler. I had a mechanic install it by the way. Thanks for your help.

 

One more thing. I checked out the detailed explanations on the FAQ, and it said a cuase could be a faulty or dischrged battery. Two days ago. I went to crank my car but nothing happened. I opened the hood and saw that the hyperground kit was loose. The negative battery cable was connected on top of the circle plate with connectors. In the end I added a one neative battery terminal head to the side of the battery reading negative and left the hyperground kit connected to the negative battery terminal (the original place where the stock connector was). Could this be the culprit? The factor starts and runs fine now, so I'm thinking maybe the code could have resulted from that incident because there were short zapping noises when I was relocating things there.

 

have you done the drop resistor mod?

 

I haven't done the resistor mod. I checked the battery connections. There's nothing worng with the car in regards to electrical or mechanical. I reset the ECU last night. It hasn't come back since. I'm keeping my fingers crossed. I don't want to get that sinking feeling when it suddenly comes on while driving.