I have a 2000 Mazda 626 A/T with approx 103k. About 2 weeks ago during highway driving, the O/D light began to flash. I took it to get the code read, but the shop said that no code was stored, and the car drove normal for the next 2 weeks. Then, during another highway trip, it began to flash, and the RPMs began to increase when going up hills.I also noticed that when coming to a stop and starting again, the cars shifts pretty rough into 1st and 2nd( or 2nd and 3rd). What could be causing the light to flash? I know that you have to read the code, but I dont think that the code will store. Is there a common problem associated with the O/D light flashing? Thanks for your help.
When the O/D Light flashes, it indicates an error has been detected in the transmission control system and the harsh and erratic shifting is an indication of that.
Some codes are not stored and the only way is to plug in the scan tool without turning engine off when the O/D lighst starts to flash to read the code.
Since problem is intermittent, it could be a loose or contminated connector and this is going to get worse in time to come. Check the transmission wireharness connector pack for presensce of water and signs of contaminations to the terminals.