Have a Honda Question? Ask a Honda Repair Expert.
a flashing 'D4 ' light means a fault with the transmisson
which can prevent the engine from cranking but the most likley source is a faulty 'main' relay thats called out in the fuse box as the PGFM unit
Its a large multipurpose unit that runs the ECU, transmisson controller and a few others so I'd suggest to pull that out and replace it
do you still need help?
Bear in mind that the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. I am only paid for my work on this question if you rate my answer, using the star system at the top of the screen. Please do not forget! Thank you