1993 Honda Accord, just bought it 2 weeks ago drove fine. Was on highway and car down shifted on its own. Got it home and changed cars and went to zoo. When I got back about 4 hrs. later I drove it and it on highway about 10 miles it shifted fine, when i stopped and turned around ti would not shift at all. The D4 was bit blinking, i checked codes and got 1,2 and 8. This says none of the solenoids are working. Im not a transmission expert, but i dont think all would go bad at same time. How do i test TCM? Would appreciate any help. Thank you