Hello all. I have been searching this issue and have not found a whole lot of useful info pertaining to my particular problem. Bear with me as I will describe things the best i can.

I have a 92 accord. Last week I was having a strange D4 light problem. I know what everyone is thinking right off the bat haha, but I replaced my TCU a year ago and the symptoms were similar, but not the same.

The first thing was when I was driving my trans went into limp mode, but the d4 light wouldnt come on (in any gear) until i was at a complete stop. D4 would flicker when driving in d3, and turn off completely driving in d4. Sometimes driving in d4 it would pop on and drive normally. I thought it could be my main relay so I resoldered it. I reinstalled it but noticed that my cruise control box that I had to remove to get to the relay was sparking when it touched the metal on my brake pedal! This made my d4 light pop on when in P!!! I saw that my alarm system was grounded to my cruise control box and ended up ripping it all out in the end. I thought all was solved, and aside from one incident on the highway where the d4 light went out and the car jerked for about 5 mins, things have been good. In that case the d4 light came back on quickly and no problems like that since.

Now, when I accellerate I notice the D4 light dimming. It does not happen all the time and never at highway speeds. I know this is an issue for alot of odysseys and later model accords, but not my gen. as far as I know. Yesterday I checked all grounds and installed a new alternator connector (as the wiring on mine was stripped of insulation at the connector) but it still dims. I am assuming the best and that the one quick occurance with my d4 light on the highway was due to my alternator pigtail, as it has not happened again yet. Does anyone think this d4 dimming might be due to my main relay? maybe I didnt solder it well enough or need a new one?? Could some other electrical issue be the cause???

 

I know my last post was loooong winded, but just wanted to see if anyone with my gen accord (92) has had this issue. My D4 light is still dimming when i hit the gas, and then coming on very bright when I let off.
I have had no other issues with limp mode since fixing my alternator pigtail (knock on wood) but this issue is knawing at me a little. It seems like a voltage issue and my alternator seems to be working as it should.
I never noticed this happening before I resoldered my main relay and disconnected my alarm system