oh my god man, you really did some damage?
JK, anyway if you have a jumper wire and a DMM (digital multimeter) I can help you diagnose this.
First things first, reset the ECM. Just pull the number 6 fuse for 10 seconds and then put back in. Then start the engine and turn the headlights on and check for the same code. If it isnt there, you had an intermitent failure. check the connections at the ELD (electrical load detector).
If it came back, turn the headlights and ignition off. disconnect the ELD 3P connecter. the ELD is behind the under hood fuse box. Underneath it actually.
Then turn the ignition on. And measure voltage between body ground and the ELD 3P connecter terminal no. 1. terminal no. 1 is the black/orange wire. Backprobe it on the harness connecter.
If there isnt battery voltage, check the no. 4 fuse, if it is ok, repair the open in the wire between the no. 4 fuse and the ELD.
If there is battery voltage, turn the ignition off. Connect the ELD 3P connecter terminal no 3. to body ground with a jumper wire. No 3 terminal is a green/red wire. Again backprobe it with a pin and connect the jumper wire to the Pin.
then disconnect the ECM/PCM connecter E (31P). Check for continuity between body ground and ECM/PCM connecter terminal E15. It is the green/red wire at terminal 15. Is there continuity?
If no, repair the open in the wire between the ECM E15 and the ELD.
If yes, check for continuity between the ELD 3P connecter terminal no. 2 and body ground. terminal 2 is a black wire. Is there continuity?
If no, repair the open in the wire between the ELD and G201 which is ground connection.
If yes, reconnect the ELD connecter and the ECM connecter. Start the engine and let it idle.
While measuring voltage between ECM/PCM connecter terminals A24 (brown/yellow wire) and E15 (green/red wire), turn the headlights on high.
Does the voltage drop?
If no, replace the ELD.
If yes, update the ECM or replace it.
Hope this helps. If you have any questions, feel free to ask.