Battery light on after installing hondata 05-06 RSX

[808to702]

Hey I’m new here and to the scene but have a friend helping me as I jump into it. I recently bought his hondata ECU and 05-06 jumper harness out of his 05 RSX type s and installed it into my 06 RSX type s. Both stock k20 with just cold air intake and exhaust. After installing hondata I now have a battery light on. We swapped it back into his and no battery light present. With my stock ECU I have no battery light on, only as soon as we put the hondata back into my vehicle. I’ve seen this come up before as I searched on this forum but no fixes that I could see. We checked ground and alternator voltage and its charging as it should at 14.2 volts. I saw that some people has this issue and just left the light on since it was charging properly. Any help is appreciated. We pretty much have identical setup so I don’t understand why his has no light on when in his car but in my car it turns the battery light on.

[Spunkster]

If it does not do it in his vehicle with the same ECU it does not appear to be an issue with the ECU or harness and is something specific to your vehicle. You might try checking the grounds in the engine bay.

https://hondata.com/tech-k-series-engine-ground

[808to702]

I have also tried moving my ground there while we were trying to troubleshoot it. Removed battery terminals cleaned them up good with wire brush, cleaned battery post side. Relocated the ground onto valve cover. Cleaned and checked transmission ground. Cleaned ground by engine mount. I am stuck on what to check next. Vehicle alternator output is within factory specs.

If it does not do it in his vehicle with the same ECU it does not appear to be an issue with the ECU or harness and is something specific to your vehicle. You might try checking the grounds in the engine bay.

https://hondata.com/tech-k-series-engine-ground