Hondata

I have an 02 RSX and have had my kpro for nearly 3 years now I think? I've relocated my ground to the valve cover and also have a grounding kit. I've read the sticky and thought it was my battery. I was still going on my stock battery. Last month I was given an Optima yellow top and I installed it. Everything was good up until this weekend. CEL came back on and daughterboard communication error. Clear and it comes right back. I'm still able to datalog and upload changes. What else could cause this error? Is it the battery?

Double check the battery terminals are secure. Is the battery relocated?

What battery voltage do you see while datalogging, with both the engine running and not running?

The battery has not been relocated. Stock stereo as far as electronics. I'll have to datalog and check the voltages on and off. Car doesn't get driven until like the weekends so it just sits quite a bit. I did notice that when I changed the battery, there was white corrosion on the positive terminal I think. I used a wire brush to clean it off. I'll double check that again.

Battery voltage while running is 14.30-14.50. Jumps around a bit. I forgot to datalog without engine running. I did re-upload my kal from a different laptop. Could a corrupted kal cause that db error? Normally after the light goes away, it's comes back within 15 minutes or so. Today after I uploaded from my back up laptop that has my original tuned kal, the CEL never popped back after several hours. I'm just curious if the kal that's in the other laptop has something corrupted which throws this CEL?

No, the calibration cannot cause the daughterboard error. Note that it is the battery voltage while cranking which matters. If that is ok, then the kpro board socketing would be the next thing to look at.